To me, it sounds like U.W. Lang speaks of several different orientations. Sometimes the people faced the altar while the priest faced the people, so that priest and people looked at each other, like today. If the people and the priest looked at each other, some churches, but not all, had the people turn around during the Eucharistic prayer to face the same direction the priest was, while others didn’t make anybody turn around. Other churches had some people sit on benches along the walls. Some people sat with their chairs facing north and others sat with their chairs facing south, and the people looked at each other, or at the priest, or East during the Eucharistic prayer, or West if that’s where the altar was, but it all depended on local custom. The custom doesn’t exactly sound uniform from U.W. Lang’s description. Am I missing something?
In the quote I gave, Lang discusses two theories as to what would have happened in churches that had their entrance in the east and the apse in the west: that of Fr. Louis Bouyer (the people turned their back on the priest and the altar to face the church doors) and Klaus Gamber (the people were on the side aisles so they did not literally have to turn their back on the altar, but instead just turn slightly to their right or left).
Lang goes on to note objections raised by others to Bouyer’s and Gamber’s theories respectively. Bouyer’s scenario has been criticized, he says, for postulating that the congregation would have turned their back on the holy altar. Gamber’s theory that the congregation stood mainly on the side aisles and left the central nave open was also questioned, because the side aisles would have also used for extra-liturgical functions. Besides, what if there was a kind of corridor or
solea running down the nave, which left most of it open for the congregation to stand on (again, no pews back then)?
Lang does, however, still accept the idea that in such churches, the priest and the congregation may have turned to the entrance in the east for the Eucharistic prayer, citing Jewish custom of praying towards the direction of Jerusalem or the east and synagogues where the entrance faced either Jerusalem or the east, thus requiring the congregation to face the entrance in prayer.
Equally controversial is the view that in basilicas with an eastern entrance the whole assembly turned towards the doors. However, our judgement in this issue should not be governed by modern sensibilities. In the context of religious practice in the ancient world, this liturgical gesture does not appear as extraordinary as it might seem today. The general custom in antiquity was to pray towards the open sky, which meant that in a closed room, one would turn to an open door or an open window for prayer. This is well attested in Jewish and Christian sources, for example Daniel 6:10, Tobit 3:11, and Acts 10:9. The Babylonian Talmud transmits a ruling of Rabbi Hiyya bar Abba to the effect that one must not pray in a room without windows. In his treatise On Prayer, Origen discusses the problem that arises if a house has no doors or windows facing east. He argues that one should turn towards the east, because this is a basic principle of Christian prayer, whereas turning towards the open sky is just a convention.
There is archaeological evidence of Galilean synagogues from the late 1st century AD with the entrance facing towards Jerusalem. Where this was the case, it would appear that the assembly turned towards the open doors for prayer and thus looked towards the direction of the sacred city. Moreover, facing east in prayer was also known to the Jewish tradition (for example, Wisdom 16:28), both among the Essenes and in the rabbinical Judaism of the first centuries AD. There are synagogues from the second to the fourth century with the doors on the eastern side of the building. The community in a synagogue with the entrance facing east turned presumably towards the doors, not towards the west wall. Against this background it would seem possible that for the eucharistic prayer the faithful, along with the priest, turned towards the entrance in the east.
Lang then proposes another possible theory: instead of facing literal east (i.e. the church entrance), maybe the priest and the congregation could have just looked up towards the apse - ‘liturgical east’ - which was decorated with mosaics which “might have served to direct the attention of the liturgical assembly, whose eyes were raised up during the eucharistic prayer.” He admits that “[t]his theory is rather tentative and requires much further scrutiny; nonetheless, its definite advantage is that it accounts better for the correlation between liturgy, art and architecture than the ideas of Bouyer and Gamber, which need to put up with a discrepancy between the sacred rites and the space created for them.”
Even if we assume that priest and people were facing one another in early Christian basilicas with an eastward entrance, we can exclude visual contact at least for the canon, since all prayed with arms raised, looking upwards. At any rate, there was not much to see on the altar, since ritual gestures, such as signs of the cross, altar kisses, genuflections and the elevation of the eucharistic species, were only added later. Christians in the ancient world and in the early Middle Ages would not have associated real participation in the liturgy with looking at the celebrant and his actions.