Schaff, Philip. History of the Christian Church (The Complete Eight Volumes in One). Amazon Kindle Edition, 2014.
Volume 2, Ante-Nicene Christianity A.D. 100-325, “Chapter 5. Christian Worship” (Includes an introduction and sections 59-74).
§59. Places of Common Worship
Schaff observes that many books about Christian worship and architecture begin with the time of Constantine. In the primitive period, it appears that worship was relatively simple. There was, however, solemn ritual. Schaff notes that through the second century churches mostly met in homes or in places of significance, such as near the graves of martyrs (Schaff 2014, Loc. 14782). The importance was in the gathering rather than the place. This was an assertion of the omnipresence of God. The triclinium of a house was normally well suited, as it was a spacious room and often had a natural elevated focal point (Schaff 2014, Loc. 14789). By the time of Tertullian and of Clement of Alexandria there were some buildings apparently set aside for worship. “After the middle of the third century the building of churches began in great earnest” (Schaff 2014, Loc. 14795). However, the first actual description we have comes from Eusebius. He describes a church built in Tyre between 313 and 322 (Schaff 2014, Loc. 14802). It seems that the altar was at the east. Bishops and elders would be seated in that area. Others would be in the nave, to the west (Schaff 2014, Loc. 14808).