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:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.