How many children did King Henry IV have? What where their names? When where they born? Do they have any still living relatives?
Henry IV had six children with his first wife, Mary de Bohun:

- Henry, born 1386, succeeded his father as King of England, and is known historically as Henry V.
- Thomas, born 1387, also known as Thomas of Lancaster, was Duke of Clarence. Thomas married Margaret Hooland, but died without progeny.
- John, born 1389, was Duke of Bedford, married twice, but died without progeny.
- Humphrey, born 1390, was Duke of Gloucester, married twice without progeny, but had two illegitimate children by an unknown mistress.
- Blanche, born 1392, married Louis of Germany, bore one son, Rupert, and died while pregnant with a second son. Rupert died at 19, unmarried and without progeny.
- Phillippa, born 1394, married Eric of Pomerania, king of Denmark, Norway and Sweden, but bore only a stillborn boy.

Henry had one illegitimate child by an unknown mistress; Edmund Leboorde, born 1401.

Little is known about Edmund Leboorde, or Humphrey's illegitimate children Arthur Plantagenet and Antigone of Gloucester, but Antigone had three children, one of whom at least, Richard Grey, had two children.

Henry V had one son, Henry VI, who had one son, Edward of Westminster, Prince of Wales, who married Anne Neville, but died at the age of 17, and there is doubt that the marriage was ever consummated.

As such, any surviving descendents would be related via illegitimate children. While it is possible there are living relatives, it is difficult to know for certain.