[Petrosius]

Note to everyone: Cardinal Sarah is speaking about liturgical east, not geographical. Early churches were built with the altar at the east end of the building. When Mass was being said the priest and the congregation would both face east toward the altar, facing in the same direction as the sacrifice was offered to the Father. Even when the church is built with a different orientation, the rubrics would call the direction that the congregation would face toward the altar "east".

What Cardinal Sarah is speaking of is the priest and the congregation facing the altar together. This is opposed to the general current practice of the priest standing on the other side of the altar and facing the congregation, called "versus populum." This recent innovation tends to suggest that the Mass is merely a communal meal recreating the Last Supper. The ancient orientation (which by the way literally means "toward the east") brings out more clearly the Mass as a sacrifice with the priest and congregation joined together in addressing God the Father.

[opus1]

Thank you! To elaborate a bit more:

Liturgical and geographical east were the same thing, and not only in the “early” days but up until almost present day. “Ad orientem” literally means “toward the east” or “facing east” which we now modify to “toward the altar”.

Canon Law required churches to be built toward the east in actuality, not figuratively; it was literal. Look at any Catholic church more than 100 years old, and many more recent, and it faces precisely east by the compass. Dispensation was required to build it otherwise (eg: if required by topography).

Recall no “vigil” mass existed either. Everyone was at morning mass, facing east, the priest and people together, as the sun rose, symbolic of course of the Son, and shone upon them. To allow this light in was the reason for rose windows and stained glass windows on the eastern side of churches.