Château de Châteaudun was built between the 12th and 16th centuries. The Count of Blois Thibaut V had the keep built around 1170. The Sainte-Chapelle was built between 1451 and 1493. The choir and the high chapel were built between 1451 and 1454, with the nave and the oratory between 1460 and 1464. Jehan de Dunois, the bâtard d'Orléans (Bastard of Orléans), built the west wing (the "aile Dunois") between 1459 and 1468. The bell tower was erected in 1493.
François I of Orléans-Longueville began construction of the north wing between 1469 and 1491. The upper floors were added by François II d'Orléans-Longueville and his descendants during the first quarter of the 16th century.
Today the castle includes a keep, a chapel (Sainte-Chapelle), the Dunois wing and the Longueville wing. Château de Châteaudun overlooks the Loir river. Perched on a limestone outcrop, it shows its origins as a 12th century fortress. Converted during the Renaissance into a comfortable residence, the main body of the building is roofed in the gothic style. It still has, notably, a finely carved staircase from this period. Renovated since the 1930s, the castle has been classed as a historic monument since 1918.
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.