then developed during the 13th century in the grand mendicant convents of the city, before spreading in the 14th century to a large number of churches and cathedrals in the region. Several churches or convents in Toulouse belong to this architectural trend, but two of them are particularly symbolic and remarkable: Cathedral of Saint-Étienne (Saint Stephen) is the seat of the Roman Catholic Archdiocese of Toulouse. Its construction, which was mainly done at the beginning and then at the end of the 13th century, reflects the history of this decisive century which saw the city lose its independence to become a French city. The single nave is the first example of Southern French Gothic, at 19 metres wide it probably was at its completion the widest in Western Europe (1210-1220). The higher choir that adjoins it was built in the Gothic style of northern France shortly after the city became part of the Crown of France in 1271. Convent of the Jacobins (13th century / early 14th century) was the Dominican convent of Toulouse and is considered to be, together with the Albi Cathedral, the pinnacle of Southern French Gothic architecture. Like all Southern French Gothic churches it has a deliberately austere exterior, but on the inside its alignment of cylindrical columns form one of the tallest colonnades ever erected in Gothic architecture (28 metres high). The masterpiece of this church is the column that closes the choir (1275-1292), its palm tree shape was a hundred years ahead of the flamboyant gothic fan vaults. Because he thought that the bones of Saint Thomas Aquinas deserved «the most beautiful and most splendid surroundings», in 1368 Pope Urban V made the church of the Jacobins the burial place of the famous Dominican friar, one of the most notable philosophers and theologians of the Middle Ages. Gothic civil architecture Toulouse has preserved about thirty Gothic stair towers (plus a dozen Renaissance or later towers), the remains of private mansions (called hôtels particuliers) from the Middle Ages and the early 16th century. Often hidden in courtyards, some of these towers are high enough to exceed their function of serving the floors and display the ambition of their owners. At a time when most of the houses in Toulouse were built in wood or cob, the brick construction of these towers and hôtels also testifies to their quality. Renaissance architecture (16th c.-early 17th c.) In