Catholic Encyclopedia (1913)/Narthex
In early Christian architecture a portion of the church at the west end, separated from the nave by a low wall or screen and reserved for the catechumens, energumens, and penitents who were not admitted amongst the congregation. The narthex was of two kinds, exterior and interior: the former consisted of an open atrium arcade continued across the front of the church; in the latter, the aisle and gallery were returned across the nave. A survival of the exterior narthex may be found in the church of San Ambrogio at Milan; of the interior narthex, in Santa Agnese, at Rome. The outer narthex was sometimes used as a hall of judgment and for other secular purposes, and, after the sixth century, as a place of burial, while the inner narthex sometimes called the matroneum, was used, probably for certain persons of rank or distinction, rather than as a women's gallery. After the abandonment of the atrium in the West, about 1000, the narthex developed by degrees into the great west porch which is so characteristic of the churches of southern France. Among the monastic orders it continued in use down to the beginning of the thirteenth century as, for example. in the abbeys of Cluny and Vézelay. With the full development of Gothic it disappeared, its place being taken by the three great western porches or doorways. Properly speaking, the name should have ceased with the function and the so-called narthex of medieval churches and abbeys should justly be called a porch. For the same reason there is no excuse for the recent revival of the word as a designation either of an exterior porch, or an interior vestibule.
Ralph Adams Cram.