Domus ecclesiae of Dura-Europos - the house church at Dura is the earliest identified Christian house church. Originally it was the well-to-do house converted into a church. The surviving frescoes of the baptistry are probably the most ancient Christian paintings. The image of "Good Shepherd", the "Healing of the paralytic" and "Christ and Peter walking on the water date to 235 AD.
Sources:
- Carl Hermann Kraeling, The Excavations at Dura-Europos. Final Report. Volume VIII, part 2. The Christian building, os Angeles : Univ. of California, 1967
- Michael Peppard, The World’s Oldest Church. Bible, Art, and Ritualat Dura- Europos, Syria, Yale University Press, New Haven & London 2016
- Richard Bernheimer, “An Ancient Oriental Source of Christian Sacred Architecture.” American Journal of Archaeology, vol. 43, no. 4, 1939, pp. 647–668. JSTOR, www.jstor.org/stable/498990. Accessed 6 Jan. 2021.