Entering the choir we see before us the high altar with a fine reredos behind it, so called from the French _L'arrière-dos_, meaning "embroidered hangings." On the south of this is the piscina, consisting of a hollow basin with a stone-drain, wherein the priest cleansed the sacred vessels after using them in the Holy Eucharist. On the same side are the sedilia, or stone seats for the clergy, frequently with richly-carved canopies. Then there are the beautifully-carved stalls with fine tabernacle work, and the _sub-sellæ_ or misereres (French, _miséricorde_) with their quaint carvings. It is a popular error, gravely perpetrated by some cathedral vergers and others, to suppose these misereres were a kind of ingenious trap for sleepy monks, who, when the heavy seat fell down with a loud bang, were detected in slumber and forced to do penance. They were so placed as a concession to human weakness in order that the monks or canons might lean against them during the long mediæval services, when sitting was not allowed. The eastern portion of the choir is called the presbytery.
We pass to the north aisle of the choir and proceed to the ambulatory, processional path, or retro-choir. Here, at the back of the altar, was the chief shrine, where the relics of some great saint were preserved under a gorgeous cover decorated with gold and silver and precious jewels, to which crowds of pilgrims flocked, and there prayed and gazed upon the wondrous shrine, and made their offerings. The steps and pavement leading to the shrine often still show by their worn condition the evidence of the tread of countless numbers of pilgrims. Near the shrine was a watching chamber, where a monk stayed to guard the shrine and its treasures.
Eastward of the ambulatory is usually the Lady Chapel, where the altar of the Virgin stood; and here, and in other parts of the church, are numerous chantry chapels, sometimes built on to the church, or in the church itself, containing effigies of the founders and altar tombs, where masses were said by specially-endowed chantry priests for the repose of the souls of the deceased and their families. Some effigies of knights and warriors have their legs crossed. It is another popular error to suppose that this fashion of representing the deceased had anything to do with the Crusades. Beneath some portion of the church we find a crypt with the remains of numerous altars, where masses were said for the souls of those who lie buried here.