Sanctuary as a sacred place

In Europe, Christian churches were sometimes built on land considered as a particularly 'holy spot', perhaps where a miracle or martyrdom had taken place or where a holy person was buried. Examples are St. Peter's Basilica in Rome and St. Albans Cathedral in England, which commemorate the martyrdom of Saint Peter (the first Pope, according to Catholics) and Saint Alban (the first Christian martyr in Britain), respectively. The place, and therefore the church built there, was considered to have been sanctified (made holy) by what happened there. In modern times, the Roman Catholic Church has continued this practice by placing in the altar of each church, when it is consecrated for use, a box (the sepulcrum) containing relics of a saint. The relics box is removed when the church is taken out of use as a church. In the Eastern Orthodox Church, the antimension on the altar serves a similar function. It is a cloth icon of Christ's body taken down from the cross, and typically has the relics of a saint sewn into it. In addition, it is signed by the parish's bishop, and represents his authorization and blessing for the Eucharist to be celebrated on that altar.

The Altar

The area around the altar was also considered holy because of the physical presence of God in the Eucharist, both during the Mass and in the tabernacle on the altar the rest of the time. So that people could tell when Jesus was there (in the tabernacle), the "sanctuary lamp" would be lit, indicating that anyone approaching the altar should genuflect (bow by bending the knee and inclining the head), to show respect for Him. In the Eastern Orthodox Church, Eastern Catholic Churches of Byzantine rite and Coptic Orthodox churches, the sanctuary is separated from the nave (where the people pray) by an iconostasis, literally a wall of icons, with three doors in it. In other Oriental Orthodox traditions, a sanctuary curtain is used. In most Protestant Churches, the term sanctuary denotes the entire worship area while the term chancel is used to refer to the area around the altar-table. In many traditions, such as the Anglican Church, Roman Catholic Church, and United Methodist Church, altar rails sometimes mark the edge of the sanctuary or chancel.

The area around the altar came to be called the "sanctuary," and that terminology does not apply to Christian churches alone: King Solomon's temple, built in about 950 BC, had a sanctuary ("Holy of Holies") where the tabernacle ("Ark of the Covenant") was, and the term applies to the corresponding part of any house of worship. In most modern synagogues, the main room for prayer is known as the sanctuary, to contrast it with smaller rooms dedicated to various other services and functions.