Technically the stone on which the Holy Sacrifice of the Mass is offered, typically containing relics of the saints.

It consists of two parts: the mensa and the base.

The altar is set on the predilla or footpace, and is typically covered in front by the frontal and across the top by the fair linen.

In addition to the high altar in the sanctuary of the church, there are four other altars at the cathedral:

• Martyr's chapel altar

• Holy House altar

• Altar at the outdoor shrine

• Bishop's oratory - in the chancery