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What is Theochrone ?

Theochrone is a liturgical calendar for the Traditional Rite. You can enter a date, and it gives you the feasts for this date, with their class, liturgical time, colour, and much more. You can also search a feast by keywords. Many other options are available.

Core Features

  • The roman calendar of 1962, accessible by dates or by keywords. A range of dates, or a period (a week or a month, for instance), is also a good option to have a better look.
  • Twelve national propers: Australia, USA, Brazil, Canada, England, France, New Zealand, Poland, Portugal, Scotland, Spain and Wales.
  • Diocesan propers:
    • France
      • Strasburg [NEW]
  • The calendar is connected to a website which provides the texts for the mass and the office of the feast.
  • The Roman martyrology, used in 1962, accessible by date or by keywords.




The website provides you basic tools: search by date, by keywords and for a whole month. The Roman Martyrology is also available. See here :


The Widget provides very limited infos, but can be a great feature on a website. For an example, see here :


The twitter interfaces manages a bot sending to every follower of the bot the feasts of the day. Any account can become a bot, even an existing one, but creating a Twitter app is required first.

Theochrone on Twitter

Web Services

Not yet available

We want to create a Rest API to give you a complete control over the raw data. Why is it unaivalable now ? Web Services are really costly in term of resources. We need money to afford better servers. We also haven't got enough time to make it and we need help to create this API. Feel free to contribute.

Graphical User Interface (GUI)

The Graphical User Interface (GUI) provides more infos. It is downloadable and can be used on any platform: Windows, macOS or Linux (even on BSD or some rarer OS).

Command-line (CLI)

The command-line interface (CLI), available with every GUI, is the fastest and the most powerful way to use the Theochrone - but it is a bit rough for computer users not familiar with CLI. For more info, type in a terminal after downloading the program: theochrone --help

Install from GitHub

  1. Clone or download repository.
  2. Open a console/terminal in the folder where you can find your clone/downloaded file.
  3. Unzip it if necessary.
  4. Install python3.5 or greater if it is not yet done. You also need to install the Python Development package. Please consult the documentation for your own OS and architecture on
  5. If necessary, install programs and libraries required to use Theochrone: GNU Gettext, Qt5. Download them for your own OS and architecture if they are not installed on your computer.
  6. Enter following commands:
python -m pip install -r requirements.txt # in many OSes, you should enter python3 instead of python, or python3.5
python -m pip install -r dev_requirement.txt # only if you want to contribute to the project
msgfmt programme/i18n/fr_FR/LC_MESSAGES/messages.po -o programme/i18n/fr_FR/LC_MESSAGES/ # if you want to use CLI with french translation. Gettext must be installed before.
python -c "import os; os.mkdir('programme/data')"
python -c "import dataswitcher; dataswitcher.main(propers='all',ordo='1962')"
python -c "import dataswitcher; dataswitcher.xml_to_pkl('en_roman_martyrology');dataswitcher.xml_to_pkl('fr_roman_martyrology_1962')" # if you want to use roman martyrology
lrelease programme/gui/i18n/ # if you want to use the GUI with french translation. Qt5 must be installed first.
lrelease programme/gui/i18n/theochrone.en.ts # if you want to use the GUI with english translation

Note that the version you download from Github may be broken. Feel free to contribute to fix the issue !

Who are we ?

We are two young french catholics. We are neither professional programmers (our jobs have almost nothing to do with programming), neither priests (we two are married), but we love our religion and her liturgy, and we love programming. Many other persons have helped us: do not hesitate to take a look at our file. You can also join us and contribute : we have HUGE needs in many domains, including programming, translating, and resources.


Maybe you can give us a little bit of help ? We need you in these domains:

  • translations, especially in:
    • english
    • spanish
    • italian
    • portuguese

but any language is accepted, even Papuan language or Sindarin !

  • programming, especially the frontend and the GUI
  • researching resources, including:
    • pictures for every feast
    • local calendars (especially diocesan)
    • older versions of the martyrology
    • other latin rites, like Sarum, or the Mozarabic

Do not hesitate to look at the issues !

We also like suggestions. Three important features have been suggested and are now implemented:

  • the widget
  • the Roman Martyrology
  • the export to calendars like Outlook, Google Calendar or iCal

We really listen to your desires and requests, so feel free to suggest or ask us something new.

Languages and Frameworks

If you're interested in some form of collaboration, do not hesitate to have a look at this list. Also, this list may change one day, especially if you put forward something else.

  • Core: Python 3.5
  • Web
    • Backend: Django 1.10
    • Frontend: Bootstrap 3
      • HTML5/CSS3
      • Javascript with jQuery
  • GUI: PyQt5
  • Others:
    • Bash/Zsh

Introducing other language

You want to contribute to Theochrone but you want to use your personal favorite language? You're welcome, but...

  • if it is an interpreted language, like PHP, Perl, Ruby, be sure that it is worth to add a whole new interpreter ; your contribution must be very huge : a new important feature, at least. Indeed, imagine the weight of the program with two or more interpreters...
  • if it is a compiled language, like C, Go, Rust, be sure that your module can be compiled on major architectures and OSes.


Latest version is 0.6.1

New features available in 0.6.1

  • New diocesan proper: Strasburg
  • GUI: export: it is now possible to select which items to export