Versus populum

Versus populum (Latin for "towards the people") is the liturgical stance of a priest who, while celebrating Mass, faces the people from the other side of the altar. The opposite stance, that of a priest facing in the same direction as the people, is today called ad orientem (literally, "towards the east" − even if the priest is really facing in some other direction) or ad apsidem ("towards the apse" − even if the altar is unrelated to the apse of the church or even if the church or chapel has no apse).

In the early history of Christianity it was considered the norm to pray facing the geographical east. From the middle of the 17th century, almost all new Roman Rite altars were built against a wall or backed by a reredos, with a tabernacle placed on the main altar or inserted into the reredos. The altars of Evangelical-Lutheran churches were built against the eastern wall of the church, likewise. This meant that the priest turned to the people, putting his back to the altar, for a few short moments at Mass.

The celebration of the Mass versus populum was suggested in 1526 by Martin Luther in the German Mass who stated that "the priest should always turn himself towards the people as, without doubt, Christ did at the Last Supper" though he noted that immediately implementing this liturgical stance was not compulsory, and that versus populum might become the normative practice with time. After the Second Vatican Council, Catholic churches "pulled the altar from the wall and made it appear to be a table" and Evangelical-Lutheran churches constructed after that time generally followed the same practice, which allowed the presider "to face the congregation as a gathered community".