Tourbillon Castle was built sometime between 1290 and 1308 by the Bishop of Sion, Boniface de Challant, as his principal residence. After Boniface died in 1308, his successor Aymon II de Châtillon probably finished the castle. In 1352 the Upper Valais revolted against Bishop Guichard Tavel. Led by Peter de la Tour, in November of that year, they marched on Sion, burned the town and unsuccessfully besieged the castle. In 1373, the Prince-Bishop bought Majorie Castle and moved his residence off the rocky spire. However, Bishop Tavel was not able to enjoy his new palace for long. In 1375 he was captured and murdered by rebels led by Peter's son, Anton de la Tour, in 1375.
Tourbillon became the Prince-Bishop's summer residence and remained a visible symbol of secular and ecclesiastical power. In 1384 a group of rebels attacked Sion and captured Tourbillon and Majoria. Bishop Eduard of Savoy had to request soldiers from Count Amadeus VII of Savoy and Bern to retake his castles.
A large part of the castle was destroyed during the Raron affair in 1417 and Bishop Wilhelm V of Raron had to flee to Bern. The castle was then rebuilt in the 1440s to 1450s by Bishop Guillaume VI of Raron. As part of the reconstruction, the chapel was repaired and painted with Gothic frescoes which are still visible. It remained the administrative center of the diocese but in later centuries the military importance of the castle decreased. On 24 May 1788, a gigantic fire in Sion reduced the castle to ashes. The Bishop planned to rebuilt Tourbillon, but the revolutions sweeping through Europe ended the plans. The castle was excavated and restored in the 20th century.
The castle ruins are located on a rocky spire above the city of Sion. Reaching the site requires climbing steep stairs that wind around the hill. The castle is surrounded by a ring wall that follows the irregular top of the spire. On the west side of the complex is a pentagonal fortified building. The 15th century chapel is located in the south-east corner. The chapel's frescoes are still intact despite the fire that destroyed the castle. A slender watch tower still stands in this corner as well. The southern wall is fortified with a square gate house. The keep is rectangular and many of the interior walls still stand.
References:Trenčín Castle is relatively large renovated castle, towering on a steep limestone cliff directly above the city of Trenčín. It is a dominant feature not only of Trenčín, but also of the entire Považie region. The castle is a national monument.
History of the castle cliff dates back to the Roman Empire, what is proved by the inscription on the castle cliff proclaiming the victory of Roman legion against Germans in the year 179.
Today’s castle was probably built on the hill-fort. The first proven building on the hill was the Great Moravian rotunda from the 9th century and later there was a stone residential tower, which served to protect the Kingdom of Hungary and the western border. In the late 13th century the castle became a property of Palatine Matúš Csák, who became Mr. of Váh and Tatras.
Matúš Csák of Trenčín built a tower, still known as Matthew’s, which is a dominant determinant of the whole building.