The Dura-Europos church, located in Dura-Europos in Syria, is the earliest identified Christian house church and one of the earliest surviving Christian churches. For the first three centuries of the church, known as Early Christianity, Christians typically met in homes because of intermittent persecution before Constantine's Edict of Milan in 313 proclaimed religious toleration throughout the Roman Empire. At many points in subsequent history, various Christian groups worshipped in homes, often due to persecution by the state church or the civil government.
The surviving frescoes in the baptistry room of the Dura-Europos church may be the most ancient Christian paintings.
"We can see the "Good Shepherd" (this iconography had a very long history in the Classical world), the "Healing of the paralytic" and "Christ and Peter walking on the water". These are considered the earliest depictions of Jesus Christ. A much larger fresco depicts three women (the third mostly lost) approaching a large sarcophagus. This most likely depicts the three Marys visiting Christ's tomb. The name Salome was painted near one of the women, who is often considered the same person as Mary Mother of James. There were also frescoes of Adam and Eve as well as David and Goliath. The frescoes clearly followed the Hellenistic Jewish iconographic tradition, but they are more crudely done than the paintings of the nearby Dura-Europos synagogue " (Wikipedia article on Dura-Europos church, accessed 12-24-2011).