Gilbert Balfour probably played the leading role in the murder of Lord Darnley

Henry Stuart, Lord Darnley

Henry Stewart or Stuart, 1st Duke of Albany , styled Lord Darnley before 1565, was king consort of Scotland and murdered at Kirk o'Field...

, consort of Mary, Queen of Scots.

Balfour married Margaret Bothwell, the sister of Adam Bothwell, Bishop of Orkney

Bishop of Orkney

The Bishop of Orkney was the ecclesiastical head of the Diocese of Orkney, one of thirteen medieval bishoprics within the territory of modern Scotland. It included both Orkney and Shetland. It was based for almost all of its history at St...

 who endowed him with the isle of Westray

Westray

Westray is one of the Orkney Islands in Scotland, with a population of around 550 people. Its main village is Pierowall, with a heritage centre, the ruined Lady Kirk and ferries to Papa Westray.-Geography and geology:...

, when it was episcopal property.

At Noltland on Westray, he had built one of the most impressive castles in the Orkney Islands, and indeed the Northern Isles

Northern Isles

The Northern Isles is a chain of islands off the north coast of mainland Scotland. The climate is cool and temperate and much influenced by the surrounding seas. There are two main island groups: Shetland and Orkney...

 was built, Noltland Castle.