Cut off at high tide only, the island of Brough of Birsay stands at the northwestern tip of the main island of Orkney called The Mainland. The former is home to major remains of Pictish and Norse settlements, the oldest of which are from Pictish-era dwellings and ironwork debris. A group of farmsteads bears witness to the Vikings who lived on Brough in the 10C and 11C. Norse earls of the Orkney Islands made Birsay one of their principal settlements on the islands.