The unique position of the Limburger Dom — at the edge of town on a rock rather than in the city center — is due to its origins as a castle chapel dedicated to St. George. The castle was probably built in Merovingian times (8th centur or earlier) and the chapel added in the early 9th century. In 910 AD, Count Konrad Kurzbold (cousin of the future King Konrad I) founded a collegiate chapter of 18 canons, who lived according to the rule of Bishop Chrodegang of Metz, on the hilltop site. The original castle chapel was torn down and a three-aisled basilica was built in its place. The foundations of this basilica have been found beneath the present floor. Construction on the Collegiate Church of St. George and St. Nicholas began around 1190 and was consecrated by the Bishop of Trier in 1235. The new church was funded in large part by the wealth acquired by Limburg merchants during the Crusades. Work continued on the west towers until about 1245. The dual patronage of the church derives from its dual purpose - it was the parish church of the citzens of Limburg, whose patron saint was Nicholas, and the collegiate church of the canons, whose patron saint was George. Each saint had his own altar and the clergy and laity were separated by a large choir screen until about 1600. The interior was destroyed by Swedish soldiers during the Thirty Years War (1618-48) and reconstructed in a late Baroque style in 1749. The Baroque renovation was heavy-handed: the surviving medieval stained glass windows were replaced; all the murals were covered up; the ribs of the vaults and columns of the arcades were painted blue and red; the capstones were gilded; the original high altar was replaced. The colorfully painted exterior was coated in plain white and the central tower was extended by 6.5 meters. The collegiate chapter of Limburg was dissolved in 1803 during the Napoleonic period, but then raised to the rank of cathedral in 1827 when the bishopric of Limburg was founded. Some renovations in contemporary style followed: the walls were coated white, the windows were redone in blue and orange (the heraldic colors of the Duke of Nassau) and towers were added to the south transept (1865). Further changes came after Limburg was incorporated into the Kingdom of Prussia in 1866. It was now the Romantic period and the cathedral was accordingly restored to an idealized vision of its original Romanesque appearance. The exterior stonework was stripped of all its plaster and paint, to better conform with the Romantic ideal of a medieval church growing out of the rock. The Baroque interior was stripped away and the wall paintings were uncovered and repainted. Further renovations came in 1934-35, enlightened by better knowledge of the original art and architecture. Art Nouveau stained glass windows were also added. A major restoration in 1965-90 included replastering and painting the exterior, both to restore it to its original appearance and to protect the stonework, which was rapidly deteriorating while exposed to the elements.