diff --git a/composer.json b/composer.json
index 0b8c90765..3e40b1cc9 100644
--- a/composer.json
+++ b/composer.json
@@ -32,7 +32,7 @@
         "psr/log": "^2.0 || ^3.0",
         "simplesamlphp/xml-common": "^1.11.2",
         "simplesamlphp/xml-security": "^1.6.5",
-        "simplesamlphp/xml-soap": "^1.2.0",
+        "simplesamlphp/xml-soap": "^1.2.1",
         "simplesamlphp/assert": "^1.0.4"
     },
     "require-dev": {
diff --git a/src/SAML2/SOAP.php b/src/SAML2/SOAP.php
index 5000b03fc..7ef5e16c5 100644
--- a/src/SAML2/SOAP.php
+++ b/src/SAML2/SOAP.php
@@ -47,7 +47,7 @@ public function getOutputToSend(AbstractMessage $message)
         // containing another message (e.g. a Response), however in the ECP
         // profile, this is the Response itself.
         if ($message instanceof SAML2_Response) {
-            $requestAuthenticated = new RequestAuthenticated(1);
+            $requestAuthenticated = new RequestAuthenticated(true);
 
             $destination = $this->destination ?: $message->getDestination();
             if ($destination === null) {
diff --git a/src/SAML2/XML/ecp/AbstractEcpElement.php b/src/SAML2/XML/ecp/AbstractEcpElement.php
index 36cd71ada..1e38221b7 100644
--- a/src/SAML2/XML/ecp/AbstractEcpElement.php
+++ b/src/SAML2/XML/ecp/AbstractEcpElement.php
@@ -11,6 +11,8 @@
  * Abstract class to be implemented by all the classes in this namespace
  *
  * @package simplesamlphp/saml2
+ *
+ * @see http://docs.oasis-open.org/security/saml/Post2.0/saml-ecp/v2.0/saml-ecp-v2.0.html
  */
 abstract class AbstractEcpElement extends AbstractElement
 {
diff --git a/src/SAML2/XML/ecp/RelayState.php b/src/SAML2/XML/ecp/RelayState.php
new file mode 100644
index 000000000..80ee6ec20
--- /dev/null
+++ b/src/SAML2/XML/ecp/RelayState.php
@@ -0,0 +1,105 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\ecp;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SOAP\Constants as C;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\TooManyElementsException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+use SimpleSAML\XML\StringElementTrait;
+
+use function boolval;
+use function intval;
+use function strval;
+
+/**
+ * Class representing the ECP RelayState element.
+ *
+ * @package simplesamlphp/saml2
+ */
+final class RelayState extends AbstractEcpElement
+{
+    use StringElementTrait;
+
+    /**
+     * Create a ECP RelayState element.
+     *
+     * @param string $relayState
+     */
+    public function __construct(
+        string $relayState,
+    ) {
+        $this->setContent($relayState);
+    }
+
+
+    /**
+     * Convert XML into a RelayState
+     *
+     * @param \DOMElement $xml The XML element we should load
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     * @throws \SimpleSAML\XML\Exception\MissingAttributeException
+     *   if the supplied element is missing any of the mandatory attributes
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, 'RelayState', InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, RelayState::NS, InvalidDOMElementException::class);
+
+        // Assert required attributes
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'actor'),
+            'Missing env:actor attribute in <ecp:RelayState>.',
+            MissingAttributeException::class,
+        );
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand'),
+            'Missing env:mustUnderstand attribute in <ecp:RelayState>.',
+            MissingAttributeException::class,
+        );
+
+        $mustUnderstand = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand');
+        Assert::same(
+            $mustUnderstand,
+            '1',
+            'Invalid value of env:mustUnderstand attribute in <ecp:RelayState>.',
+            ProtocolViolationException::class,
+        );
+
+        $actor = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'actor');
+        Assert::same(
+            $actor,
+            C::SOAP_ACTOR_NEXT,
+            'Invalid value of env:actor attribute in <ecp:RelayState>.',
+            ProtocolViolationException::class,
+        );
+
+        return new static($xml->textContent);
+    }
+
+
+    /**
+     * Convert this ECP RelayState to XML.
+     *
+     * @param \DOMElement|null $parent The element we should append this element to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = $this->instantiateParentElement($parent);
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:mustUnderstand', '1');
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:actor', C::SOAP_ACTOR_NEXT);
+        $e->textContent = $this->getContent();
+
+        return $e;
+    }
+}
diff --git a/src/SAML2/XML/ecp/Request.php b/src/SAML2/XML/ecp/Request.php
new file mode 100644
index 000000000..1ea1da605
--- /dev/null
+++ b/src/SAML2/XML/ecp/Request.php
@@ -0,0 +1,178 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\ecp;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SAML2\XML\saml\Issuer;
+use SimpleSAML\SAML2\XML\samlp\IDPList;
+use SimpleSAML\SOAP\Constants as C;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\TooManyElementsException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+
+use function boolval;
+use function intval;
+use function is_null;
+use function is_numeric;
+use function strval;
+
+/**
+ * Class representing the ECP Request element.
+ *
+ * @package simplesamlphp/saml2
+ */
+final class Request extends AbstractEcpElement
+{
+    /**
+     * Create a ECP Request element.
+     *
+     * @param \SimpleSAML\SAML2\XML\saml\Issuer $issuer
+     * @param \SimpleSAML\SAML2\XML\samlp\IDPList|null $idpList
+     * @param string|null $providerName
+     * @param bool|null $isPassive
+     */
+    public function __construct(
+        protected Issuer $issuer,
+        protected ?IDPList $idpList = null,
+        protected ?string $providerName = null,
+        protected ?bool $isPassive = null,
+    ) {
+    }
+
+
+    /**
+     * Collect the value of the isPassive-property
+     *
+     * @return bool|null
+     */
+    public function getIsPassive(): ?bool
+    {
+        return $this->isPassive;
+    }
+
+
+    /**
+     * Collect the value of the providerName-property
+     *
+     * @return string|null
+     */
+    public function getProviderName(): ?string
+    {
+        return $this->providerName;
+    }
+
+
+    /**
+     * Collect the value of the issuer-property
+     *
+     * @return \SimpleSAML\SAML2\XML\saml\Issuer
+     */
+    public function getIssuer(): Issuer
+    {
+        return $this->issuer;
+    }
+    /**
+     * Collect the value of the idpList-property
+     *
+     * @return \SimpleSAML\SAML2\XML\samlp\IDPList|null
+     */
+    public function getIDPList(): ?IDPList
+    {
+        return $this->idpList;
+    }
+
+
+    /**
+     * Convert XML into a Request
+     *
+     * @param \DOMElement $xml The XML element we should load
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     * @throws \SimpleSAML\XML\Exception\MissingAttributeException
+     *   if the supplied element is missing any of the mandatory attributes
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, 'Request', InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, Request::NS, InvalidDOMElementException::class);
+
+        // Assert required attributes
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'actor'),
+            'Missing env:actor attribute in <ecp:Request>.',
+            MissingAttributeException::class,
+        );
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand'),
+            'Missing env:mustUnderstand attribute in <ecp:Request>.',
+            MissingAttributeException::class,
+        );
+
+        $mustUnderstand = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand');
+        Assert::same(
+            $mustUnderstand,
+            '1',
+            'Invalid value of env:mustUnderstand attribute in <ecp:Request>.',
+            ProtocolViolationException::class,
+        );
+
+        $actor = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'actor');
+        Assert::same(
+            $actor,
+            C::SOAP_ACTOR_NEXT,
+            'Invalid value of env:actor attribute in <ecp:Request>.',
+            ProtocolViolationException::class,
+        );
+
+        $issuer = Issuer::getChildrenOfClass($xml);
+        Assert::count(
+            $issuer,
+            1,
+            'More than one <saml:Issuer> in <ecp:Request>.',
+            TooManyElementsException::class,
+        );
+
+        $idpList = IDPList::getChildrenOfClass($xml);
+
+        return new static(
+            array_pop($issuer),
+            array_pop($idpList),
+            self::getOptionalAttribute($xml, 'ProviderName', null),
+            self::getOptionalBooleanAttribute($xml, 'IsPassive', null),
+        );
+    }
+
+
+    /**
+     * Convert this ECP SubjectConfirmation to XML.
+     *
+     * @param \DOMElement|null $parent The element we should append this element to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = $this->instantiateParentElement($parent);
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:mustUnderstand', '1');
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:actor', C::SOAP_ACTOR_NEXT);
+
+        if ($this->getProviderName() !== null) {
+            $e->setAttribute('ProviderName', $this->getProviderName());
+        }
+
+        if ($this->getIsPassive() !== null) {
+            $e->setAttribute('IsPassive', strval(intval($this->getIsPassive())));
+        }
+
+        $this->getIssuer()->toXML($e);
+        $this->getIDPList()?->toXML($e);
+
+        return $e;
+    }
+}
diff --git a/src/SAML2/XML/ecp/RequestAuthenticated.php b/src/SAML2/XML/ecp/RequestAuthenticated.php
index 939d00983..8708228a9 100644
--- a/src/SAML2/XML/ecp/RequestAuthenticated.php
+++ b/src/SAML2/XML/ecp/RequestAuthenticated.php
@@ -11,6 +11,7 @@
 use SimpleSAML\XML\Exception\InvalidDOMElementException;
 use SimpleSAML\XML\Exception\MissingAttributeException;
 
+use function boolval;
 use function is_null;
 use function is_numeric;
 use function strval;
@@ -25,26 +26,20 @@ final class RequestAuthenticated extends AbstractEcpElement
     /**
      * Create a ECP RequestAuthenticated element.
      *
-     * @param int|null $mustUnderstand
+     * @param bool $mustUnderstand
      */
     public function __construct(
-        protected ?int $mustUnderstand,
+        protected bool $mustUnderstand
     ) {
-        Assert::oneOf(
-            $mustUnderstand,
-            [null, 0, 1],
-            'Invalid value of env:mustUnderstand attribute in <ecp:Response>.',
-            ProtocolViolationException::class,
-        );
     }
 
 
     /**
      * Collect the value of the mustUnderstand-property
      *
-     * @return int|null
+     * @return bool
      */
-    public function getMustUnderstand(): ?int
+    public function getMustUnderstand(): bool
     {
         return $this->mustUnderstand;
     }
@@ -78,20 +73,18 @@ public static function fromXML(DOMElement $xml): static
 
         Assert::oneOf(
             $mustUnderstand,
-            ['', '0', '1'],
-            'Invalid value of env:mustUnderstand attribute in <ecp:Response>.',
+            ['0', '1'],
+            'Invalid value of env:mustUnderstand attribute in <ecp:RequestAuthenticated>.',
             ProtocolViolationException::class,
         );
         Assert::same(
             $actor,
             'http://schemas.xmlsoap.org/soap/actor/next',
-            'Invalid value of env:actor attribute in <ecp:Response>.',
+            'Invalid value of env:actor attribute in <ecp:RequestAuthenticated>.',
             ProtocolViolationException::class,
         );
 
-        $mustUnderstand = ($mustUnderstand === '') ? null : intval($mustUnderstand);
-
-        return new static($mustUnderstand);
+        return new static(boolval($mustUnderstand));
     }
 
 
@@ -103,13 +96,10 @@ public static function fromXML(DOMElement $xml): static
      */
     public function toXML(DOMElement $parent = null): DOMElement
     {
-        $response = $this->instantiateParentElement($parent);
-
-        if ($this->getMustUnderstand() !== null) {
-            $response->setAttributeNS(C::NS_SOAP_ENV_11, 'env:mustUnderstand', strval($this->getMustUnderstand()));
-        }
-        $response->setAttributeNS(C::NS_SOAP_ENV_11, 'env:actor', 'http://schemas.xmlsoap.org/soap/actor/next');
+        $e = $this->instantiateParentElement($parent);
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:mustUnderstand', strval(intval($this->getMustUnderstand())));
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:actor', C::SOAP_ACTOR_NEXT);
 
-        return $response;
+        return $e;
     }
 }
diff --git a/src/SAML2/XML/ecp/SubjectConfirmation.php b/src/SAML2/XML/ecp/SubjectConfirmation.php
new file mode 100644
index 000000000..03ca304d1
--- /dev/null
+++ b/src/SAML2/XML/ecp/SubjectConfirmation.php
@@ -0,0 +1,142 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\ecp;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SAML2\XML\saml\SubjectConfirmationData;
+use SimpleSAML\SOAP\Constants as C;
+use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\TooManyElementsException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+
+use function boolval;
+use function intval;
+use function is_null;
+use function is_numeric;
+use function strval;
+
+/**
+ * Class representing the ECP SubjectConfirmation element.
+ *
+ * @package simplesamlphp/saml2
+ */
+final class SubjectConfirmation extends AbstractEcpElement
+{
+    /**
+     * Create a ECP SubjectConfirmation element.
+     *
+     * @param string $method
+     * @param \SimpleSAML\SAML2\XML\saml\SubjectConfirmationData|null $subjectConfirmationData
+     */
+    public function __construct(
+        protected string $method,
+        protected ?SubjectConfirmationData $subjectConfirmationData = null,
+    ) {
+        Assert::validURI($method, SchemaViolationException::class);
+    }
+
+
+    /**
+     * Collect the value of the method-property
+     *
+     * @return string
+     */
+    public function getMethod(): string
+    {
+        return $this->method;
+    }
+
+
+    /**
+     * Collect the value of the subjectConfirmationData-property
+     *
+     * @return \SimpleSAML\SAML2\XML\saml\SubjectConfirmationData|null
+     */
+    public function getSubjectConfirmationData(): ?SubjectConfirmationData
+    {
+        return $this->subjectConfirmationData;
+    }
+
+
+    /**
+     * Convert XML into a SubjectConfirmation
+     *
+     * @param \DOMElement $xml The XML element we should load
+     * @return static
+     *
+     * @throws \SimpleSAML\XML\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     * @throws \SimpleSAML\XML\Exception\MissingAttributeException
+     *   if the supplied element is missing any of the mandatory attributes
+     */
+    public static function fromXML(DOMElement $xml): static
+    {
+        Assert::same($xml->localName, 'SubjectConfirmation', InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, SubjectConfirmation::NS, InvalidDOMElementException::class);
+
+        // Assert required attributes
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'actor'),
+            'Missing env:actor attribute in <ecp:SubjectConfirmation>.',
+            MissingAttributeException::class,
+        );
+        Assert::true(
+            $xml->hasAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand'),
+            'Missing env:mustUnderstand attribute in <ecp:SubjectConfirmation>.',
+            MissingAttributeException::class,
+        );
+
+        $mustUnderstand = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'mustUnderstand');
+        Assert::same(
+            $mustUnderstand,
+            '1',
+            'Invalid value of env:mustUnderstand attribute in <ecp:SubjectConfirmation>.',
+            ProtocolViolationException::class,
+        );
+
+        $actor = $xml->getAttributeNS(C::NS_SOAP_ENV_11, 'actor');
+        Assert::same(
+            $actor,
+            C::SOAP_ACTOR_NEXT,
+            'Invalid value of env:actor attribute in <ecp:SubjectConfirmation>.',
+            ProtocolViolationException::class,
+        );
+
+        $subjectConfirmationData = SubjectConfirmationData::getChildrenOfClass($xml);
+        Assert::maxCount(
+            $subjectConfirmationData,
+            1,
+            'More than one <saml:SubjectConfirmationData> in <saml:SubjectConfirmation>.',
+            TooManyElementsException::class,
+        );
+
+        return new static(
+            self::getAttribute($xml, 'Method'),
+            array_pop($subjectConfirmationData),
+        );
+    }
+
+
+    /**
+     * Convert this ECP SubjectConfirmation to XML.
+     *
+     * @param \DOMElement|null $parent The element we should append this element to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = $this->instantiateParentElement($parent);
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:mustUnderstand', '1');
+        $e->setAttributeNS(C::NS_SOAP_ENV_11, 'env:actor', C::SOAP_ACTOR_NEXT);
+        $e->setAttribute('Method', $this->getMethod());
+
+        $this->getSubjectConfirmationData()?->toXML($e);
+
+        return $e;
+    }
+}
diff --git a/tests/SAML2/SOAPTest.php b/tests/SAML2/SOAPTest.php
index 8f8a5d312..ca5f7ee73 100644
--- a/tests/SAML2/SOAPTest.php
+++ b/tests/SAML2/SOAPTest.php
@@ -116,7 +116,7 @@ public function testSendResponse(): void
 <env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/"><env:Header /><env:Body /></env:Envelope>
 SOAP
         );
-        $requestAuthenticated = new RequestAuthenticated(1);
+        $requestAuthenticated = new RequestAuthenticated(true);
         $ecpResponse = new Response('https://example.org/metadata');
 
 
diff --git a/tests/SAML2/XML/ecp/RelayStateTest.php b/tests/SAML2/XML/ecp/RelayStateTest.php
new file mode 100644
index 000000000..2ae7be3b9
--- /dev/null
+++ b/tests/SAML2/XML/ecp/RelayStateTest.php
@@ -0,0 +1,101 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\SAML2\XML\ecp;
+
+use DOMDocument;
+use DOMElement;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SAML2\XML\ecp\RelayState;
+use SimpleSAML\SOAP\Constants as SOAP;
+use SimpleSAML\Test\SAML2\Constants as C;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * @covers \SimpleSAML\SAML2\XML\ecp\AbstractEcpElement
+ * @covers \SimpleSAML\SAML2\XML\ecp\RelayState
+ * @package simplesamlphp/saml2
+ */
+final class RelayStateTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/saml-schema-ecp-2.0.xsd';
+
+        self::$testedClass = RelayState::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/ecp_RelayState.xml'
+        );
+    }
+
+
+    /**
+     */
+    public function testMarshalling(): void
+    {
+        $relayState = new RelayState('AGDY854379dskssda');
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($relayState),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshalling(): void
+    {
+        $relayState = RelayState::fromXML(self::$xmlRepresentation->documentElement);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($relayState),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingMustUnderstandThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'mustUnderstand');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:mustUnderstand attribute in <ecp:RelayState>.');
+
+        RelayState::fromXML($document);
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingActorThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'actor');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:actor attribute in <ecp:RelayState>.');
+
+        RelayState::fromXML($document);
+    }
+}
diff --git a/tests/SAML2/XML/ecp/RequestAuthenticatedTest.php b/tests/SAML2/XML/ecp/RequestAuthenticatedTest.php
index 80a65a63c..ec2e0db70 100644
--- a/tests/SAML2/XML/ecp/RequestAuthenticatedTest.php
+++ b/tests/SAML2/XML/ecp/RequestAuthenticatedTest.php
@@ -45,7 +45,7 @@ public static function setUpBeforeClass(): void
      */
     public function testMarshalling(): void
     {
-        $ra = new RequestAuthenticated(0);
+        $ra = new RequestAuthenticated(false);
 
         $this->assertEquals(
             self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
diff --git a/tests/SAML2/XML/ecp/RequestTest.php b/tests/SAML2/XML/ecp/RequestTest.php
new file mode 100644
index 000000000..16d11b789
--- /dev/null
+++ b/tests/SAML2/XML/ecp/RequestTest.php
@@ -0,0 +1,117 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\SAML2\XML\ecp;
+
+use DOMDocument;
+use DOMElement;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SAML2\XML\ecp\Request;
+use SimpleSAML\SAML2\XML\saml\Issuer;
+use SimpleSAML\SAML2\XML\samlp\GetComplete;
+use SimpleSAML\SAML2\XML\samlp\IDPEntry;
+use SimpleSAML\SAML2\XML\samlp\IDPList;
+use SimpleSAML\SOAP\Constants as SOAP;
+use SimpleSAML\Test\SAML2\Constants as C;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * @covers \SimpleSAML\SAML2\XML\ecp\AbstractEcpElement
+ * @covers \SimpleSAML\SAML2\XML\ecp\Request
+ * @package simplesamlphp/saml2
+ */
+final class RequestTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/saml-schema-ecp-2.0.xsd';
+
+        self::$testedClass = Request::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/ecp_Request.xml'
+        );
+    }
+
+
+    /**
+     */
+    public function testMarshalling(): void
+    {
+        $issuer = new Issuer(
+            'TheIssuerValue',
+            'TheNameQualifier',
+            'TheSPNameQualifier',
+            'urn:the:format',
+            'TheSPProvidedID',
+        );
+        $entry1 = new IDPEntry('urn:some:requester1', 'testName1', 'urn:test:testLoc1');
+        $entry2 = new IDPEntry('urn:some:requester2', 'testName2', 'urn:test:testLoc2');
+        $getComplete = new GetComplete('https://some/location');
+        $idpList = new IDPList([$entry1, $entry2], $getComplete);
+
+        $request = new Request($issuer, $idpList, 'PHPUnit', true);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($request),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshalling(): void
+    {
+        $request = Request::fromXML(self::$xmlRepresentation->documentElement);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($request),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingMustUnderstandThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'mustUnderstand');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:mustUnderstand attribute in <ecp:Request>.');
+
+        Request::fromXML($document);
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingActorThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'actor');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:actor attribute in <ecp:Request>.');
+
+        Request::fromXML($document);
+    }
+}
diff --git a/tests/SAML2/XML/ecp/SubjectConfirmationTest.php b/tests/SAML2/XML/ecp/SubjectConfirmationTest.php
new file mode 100644
index 000000000..5a25fb1b5
--- /dev/null
+++ b/tests/SAML2/XML/ecp/SubjectConfirmationTest.php
@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Test\SAML2\XML\ecp;
+
+use DateTimeImmutable;
+use DOMDocument;
+use DOMElement;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\SAML2\Exception\ProtocolViolationException;
+use SimpleSAML\SAML2\XML\ecp\SubjectConfirmation;
+use SimpleSAML\SAML2\XML\saml\SubjectConfirmationData;
+use SimpleSAML\SOAP\Constants as SOAP;
+use SimpleSAML\Test\SAML2\Constants as C;
+use SimpleSAML\XMLSecurity\XML\ds\KeyInfo;
+use SimpleSAML\XMLSecurity\XML\ds\KeyName;
+use SimpleSAML\XML\Attribute as XMLAttribute;
+use SimpleSAML\XML\Chunk;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\Exception\MissingAttributeException;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * @covers \SimpleSAML\SAML2\XML\ecp\AbstractEcpElement
+ * @covers \SimpleSAML\SAML2\XML\ecp\SubjectConfirmation
+ * @package simplesamlphp/saml2
+ */
+final class SubjectConfirmationTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$schemaFile = dirname(__FILE__, 5) . '/resources/schemas/saml-schema-ecp-2.0.xsd';
+
+        self::$testedClass = SubjectConfirmation::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/ecp_SubjectConfirmation.xml'
+        );
+    }
+
+
+    /**
+     */
+    public function testMarshalling(): void
+    {
+        $arbitrary = DOMDocumentFactory::fromString('<some>Arbitrary Element</some>');
+
+        $attr1 = new XMLAttribute('urn:test:something', 'test', 'attr1', 'testval1');
+        $attr2 = new XMLAttribute('urn:test:something', 'test', 'attr2', 'testval2');
+
+        $subjectConfirmationData = new SubjectConfirmationData(
+            new DateTimeImmutable('2001-04-19T04:25:21Z'),
+            new DateTimeImmutable('2009-02-13T23:31:30Z'),
+            C::ENTITY_SP,
+            'SomeRequestID',
+            '127.0.0.1',
+            [
+                new KeyInfo([new KeyName('SomeKey')]),
+                new Chunk($arbitrary->documentElement),
+            ],
+            [$attr1, $attr2]
+        );
+
+        $subjectConfirmation = new SubjectConfirmation(C::CM_BEARER, $subjectConfirmationData);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($subjectConfirmation),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshalling(): void
+    {
+        $subjectConfirmation = SubjectConfirmation::fromXML(self::$xmlRepresentation->documentElement);
+
+        $this->assertEquals(
+            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
+            strval($subjectConfirmation),
+        );
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingMustUnderstandThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'mustUnderstand');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:mustUnderstand attribute in <ecp:SubjectConfirmation>.');
+
+        SubjectConfirmation::fromXML($document);
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingActorThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttributeNS(SOAP::NS_SOAP_ENV_11, 'actor');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing env:actor attribute in <ecp:SubjectConfirmation>.');
+
+        SubjectConfirmation::fromXML($document);
+    }
+
+
+    /**
+     */
+    public function testUnmarshallingWithMissingMethodThrowsException(): void
+    {
+        $document = clone self::$xmlRepresentation->documentElement;
+        $document->removeAttribute('Method');
+
+        $this->expectException(MissingAttributeException::class);
+        $this->expectExceptionMessage('Missing \'Method\' attribute on ecp:SubjectConfirmation.');
+
+        SubjectConfirmation::fromXML($document);
+    }
+}
diff --git a/tests/resources/xml/ecp_RelayState.xml b/tests/resources/xml/ecp_RelayState.xml
new file mode 100644
index 000000000..d008c399a
--- /dev/null
+++ b/tests/resources/xml/ecp_RelayState.xml
@@ -0,0 +1 @@
+<ecp:RelayState xmlns:ecp="urn:oasis:names:tc:SAML:2.0:profiles:SSO:ecp" xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" env:mustUnderstand="1" env:actor="http://schemas.xmlsoap.org/soap/actor/next">AGDY854379dskssda</ecp:RelayState>
diff --git a/tests/resources/xml/ecp_Request.xml b/tests/resources/xml/ecp_Request.xml
new file mode 100644
index 000000000..819c75e28
--- /dev/null
+++ b/tests/resources/xml/ecp_Request.xml
@@ -0,0 +1,8 @@
+<ecp:Request xmlns:ecp="urn:oasis:names:tc:SAML:2.0:profiles:SSO:ecp" xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" env:mustUnderstand="1" env:actor="http://schemas.xmlsoap.org/soap/actor/next" ProviderName="PHPUnit" IsPassive="1">
+  <saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" NameQualifier="TheNameQualifier" SPNameQualifier="TheSPNameQualifier" Format="urn:the:format" SPProvidedID="TheSPProvidedID">TheIssuerValue</saml:Issuer>
+  <samlp:IDPList xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol">
+    <samlp:IDPEntry ProviderID="urn:some:requester1" Name="testName1" Loc="urn:test:testLoc1"/>
+    <samlp:IDPEntry ProviderID="urn:some:requester2" Name="testName2" Loc="urn:test:testLoc2"/>
+    <samlp:GetComplete>https://some/location</samlp:GetComplete>
+  </samlp:IDPList>
+</ecp:Request>
diff --git a/tests/resources/xml/ecp_SubjectConfirmation.xml b/tests/resources/xml/ecp_SubjectConfirmation.xml
new file mode 100644
index 000000000..aa3465f75
--- /dev/null
+++ b/tests/resources/xml/ecp_SubjectConfirmation.xml
@@ -0,0 +1,8 @@
+<ecp:SubjectConfirmation xmlns:ecp="urn:oasis:names:tc:SAML:2.0:profiles:SSO:ecp" xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" env:mustUnderstand="1" env:actor="http://schemas.xmlsoap.org/soap/actor/next" Method="urn:oasis:names:tc:SAML:2.0:cm:bearer">
+  <saml:SubjectConfirmationData xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" NotBefore="2001-04-19T04:25:21Z" NotOnOrAfter="2009-02-13T23:31:30Z" Recipient="https://simplesamlphp.org/sp/metadata" InResponseTo="SomeRequestID" Address="127.0.0.1" test:attr1="testval1" test:attr2="testval2" xmlns:test="urn:test:something">
+    <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
+      <ds:KeyName>SomeKey</ds:KeyName>
+    </ds:KeyInfo>
+    <some>Arbitrary Element</some>
+  </saml:SubjectConfirmationData>
+</ecp:SubjectConfirmation>