The Church of San Dionisio was built in the late 15th century in Gothic-Mudéjar style, although its interior was later renovated in Baroque style (18th century) by architects Diego Antonio Díaz and Pedro de Silva.
The parish was established by Alfonso X the Wise in the name of Saint Denis as the city was returned to Christian rule on Saint Denis's Day in 1264.
The church has a basilica plan, divided into three naves by tall and simple pillars adorned with Almohad decorations. The arcades (aside from those near the high altar) are ogival. The naves end with apses with Baroque altars, including the high altar which dates to the pre-Baroque renovation.
The side chapels are in Baroque style. The chapel of the Christ of the Water includes an image of Jesus from the 15th century. The tower known as Torre de la Atalaya was also built in the fifteenth century. Although this is attached to the church it was a civilian construction intended to serve as a watchtower for both fires and attack and to hold the town's clock. The tower has been separately listed from the church as being of cultural interest. The tower was first mentioned in 1447 and the clock was installed in 1454 and the tower was first used as a watchtower in 1484.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians. The county became a privileged refuge for persecuted Cathars.
The castle, often besieged (notably by Simon de Montfort in 1211 and 1212), resisted assault and was only taken once, in 1486, thanks to treachery during the war between two branches of the Foix family.
From the 14th century, the Counts of Foix spent less and less time in the uncomfortable castle, preferring the Governors' Palace. From 1479, the Counts of Foix became Kings of Navarre and the last of them, made Henri IV of France, annexed his Pyrrenean lands to France.
As seat of the Governor of the Foix region from the 15th century, the castle continued to ensure the defence of the area, notably during the Wars of Religion. Alone of all the castles in the region, it was exempted from the destruction orders of Richelieu (1632-1638).
Until the Revolution, the fortress remained a garrison. Its life was brightened with grand receptions for its governors, including the Count of Tréville, captain of musketeers under Louis XIII and Marshal Philippe Henri de Ségur, one of Louis XVI's ministers. The Round Tower, built in the 15th century, is the most recent, the two square towers having been built before the 11th century. They served as a political and civil prison for four centuries until 1862.
Since 1930, the castle has housed the collections of the Ariège départemental museum. Sections on prehistory, Gallo-Roman and mediaeval archaeology tell the history of Ariège from ancient times. Currently, the museum is rearranging exhibits to concentrate on the history of the castle site so as to recreate the life of Foix at the time of the Counts.