Peel Castle — Peel, Isle of Man - Castles on Waymarking.com

Peel Castle (Cashtal Purt-ny-Hinshey in Manx Gaelic) was built in the 11th century by the Vikings, under the rule of King Magnus Barefoot, as Magnus III King of Norway and King of Dublin (1073 – 1103). While there were older stone Celtic monastic buildings on the island, the first Viking fortifications were built of wood. The prominent round tower was originally part of the Celtic monastery, but has had battlements added at a later date. In the early 14th century, the majority of the walls and towers were built primarily from local red sandstone, which is found abundantly in the area. After the rule of the Vikings, the castle continued to be used by the Church due to the Cathedral of St. German built there – the see of the diocese of Sodor and Man – but was eventually abandoned in the 18th century.
The castle remained fortified, and new defensive positions were added as late as 1860. The buildings within the castle are now mostly ruined, but the outer walls remain intact. Like the structures throughout the castle grounds, the cathedral's roof is completely missing. A pointed barrel-vaulted crypt exists below the chancel measuring 34 feet by 16 feet by 9 feet high at the west end, sloping to the entrance at the east.
Excavations in 1982-87 revealed an extensive graveyard as well as the remains of Magnus Barefoot's original wooden fort. The most spectacular finds were the 10th century grave of "The Pagan Lady" which included a fine example of a Viking necklace and a cache of silver coins dating from about 1030. The Castle's most famous "resident" is the so-called Moddey Dhoo or "Black Dog" ghost.
Peel Castle has been proposed as a possible location of the Arthurian Avalon.
Peel Castle features today on the reverse side of the £10 notes issued by the Isle of Man Government.
source: wikipedia