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:
The Mosque–Cathedral of Córdoba, also known as the Great Mosque of Córdoba and the Mezquita is regarded as one of the most accomplished monuments of Moorish architecture.
According to a traditional account, a small Visigoth church, the Catholic Basilica of Saint Vincent of Lérins, originally stood on the site. In 784 Abd al-Rahman I ordered construction of the Great Mosque, which was considerably expanded by later Muslim rulers. The mosque underwent numerous subsequent changes: Abd al-Rahman II ordered a new minaret, while in 961 Al-Hakam II enlarged the building and enriched the Mihrab. The last of such reforms was carried out by Almanzor in 987. It was connected to the Caliph"s palace by a raised walkway, mosques within the palaces being the tradition for previous Islamic rulers – as well as Christian Kings who built their palaces adjacent to churches. The Mezquita reached its current dimensions in 987 with the completion of the outer naves and courtyard.
In 1236, Córdoba was conquered by King Ferdinand III of Castile, and the centre of the mosque was converted into a Catholic cathedral. Alfonso X oversaw the construction of the Villaviciosa Chapel and the Royal Chapel within the mosque. The kings who followed added further Christian features, such as King Henry II rebuilding the chapel in the 14th century. The minaret of the mosque was also converted to the bell tower of the cathedral. It was adorned with Santiago de Compostela"s captured cathedral bells. Following a windstorm in 1589, the former minaret was further reinforced by encasing it within a new structure.
The most significant alteration was the building of a Renaissance cathedral nave in the middle of the expansive structure. The insertion was constructed by permission of Charles V, king of Castile and Aragon. Artisans and architects continued to add to the existing structure until the late 18th century.
The building"s floor plan is seen to be parallel to some of the earliest mosques built from the very beginning of Islam. It had a rectangular prayer hall with aisles arranged perpendicular to the qibla, the direction towards which Muslims pray. The prayer hall was large and flat, with timber ceilings held up by arches of horseshoe-like appearance.
In planning the mosque, the architects incorporated a number of Roman columns with choice capitals. Some of the columns were already in the Gothic structure; others were sent from various regions of Iberia as presents from the governors of provinces. Ivory, jasper, porphyry, gold, silver, copper, and brass were used in the decorations. Marvellous mosaics and azulejos were designed. Later, the immense temple embodied all the styles of Morisco architecture into one composition.
The building is most notable for its arcaded hypostyle hall, with 856 columns of jasper, onyx, marble, granite and porphyry. These were made from pieces of the Roman temple that had occupied the site previously, as well as other Roman buildings, such as the Mérida amphitheatre. The double arches were an innovation, permitting higher ceilings than would otherwise be possible with relatively low columns. The double arches consist of a lower horseshoe arch and an upper semi-circular arch.