Founded in 997 AD as Kaupangr, and later called Nidaros, Norway’s early capital has a number of major attractions, not least the Nidarosdomen Cathedral, which dates from the late 11th century. Built over St Olav’s grave, it has been a center of pilgrimage since medieval times. Elsewhere, the Ringve Museum is famous for its collection of rare historic musical instruments, while the Trøndelag Folk Museum incorporates the ruins of a 12th-century castle. Stiftsgården, the Trondheim palace of the Norwegian Royal Family, is a fine 18th-century wooden building in the city center. Across the river stands the Kristiansten Festning fortress. The former island monastery of Munkholmen in the fjord is a popular boat excursion.