Its construction began in 1162 by Henry II of England and Eleanor of Aquitaine on the ruins of a Roman basilica, and work was well advanced by the end of the 12th century. It is the largest medieval monument in the city of Poitiers.
It is built in the Romanesque and Early Gothic styles, the latter predominating. It consists of three naves almost equal in height and width, all three of which decrease towards the west, thus enhancing the perspective. Its length is 308 ft., and the keystone of the central vaulted roof is 89 ft. above the pavement. There is no apse, and the exterior generally has a heavy appearance. The principal front, which is broad relative to its height, has unfinished side-towers 105 and 110 ft. tall, begun in the 13th century.
Most of the windows of the choir and the transepts preserve their stained glass of the 12th and 13th centuries; the end window, which is certainly the first in the order of time, contains the figures of Henry II and Eleanor. The choir stalls, carved between 1235 and 1257, are among the oldest in France.
On the night of 25 December 1681 the organ was destroyed by fire. It was not until 1770-78 that a campaign was launched to build a replacement. François-Henri Clicquot, at that time the leading organ-builder in France, was appointed to undertake the work, but died in Pentecost 1790 before completing the work. His son, Claude-François Clicquot, finished the job, handing it over for presentation in March 1791. The instrument is a beautiful example of eighteenth-century organ design, and is still largely intact.