The earlier Castle Girnigoe was built by
William Sinclair, 2nd Earl of Caithness, probably sometime between 1476 and 1496, but certainly before his death at the
Battle of Flodden in 1513. There is some evidence to suggest that the castle was built on the foundations of an earlier
fortalice.
Olave Sinclair, the
foud of Shetland, was brought to Girnigoe in May 1573, paralysed after a
stroke. In 1577,
George Sinclair, 4th Earl of Caithness, imprisoned his own son
John Sinclair, Master of Caithness, in Castle Girnigoe, on suspicion of rebelling against his rule. He was held there for seven years, after which his father fed him a diet of salted beef, with nothing to drink, so that he eventually died insane from thirst. The rebel
Earl of Bothwell was at Girnigoe in December 1594. Expansion occurred in 1606 when Castle Sinclair was built, comprising a gatehouse and other buildings, along with a
curtain wall. These were connected to the earlier castle by a
drawbridge over a ravine. Robert Sinclair describes Girnigoe as "an adapted 5-storey
L-plan crow-stepped gabled tower house, which sat upon a rocky promontory jutting out into
Sinclair Bay. Of interest is the secret chamber in the vaulted ceiling of the kitchen." However, George Sinclair of Keiss continued his opposition and laid siege, with firearms and artillery, to Castle Sinclair Girnigoe which he took after feeble resistance from the garrison. As a result, he and his three friends who had assisted him, Sinclair of Broynach, Sinclair of Thura and
Mackay of Strathnaver were declared rebels. The political current having turned in favor of Sinclair of Keiss however, this was quashed. Having failed to regain his inheritance by force, Sinclair of Keiss then turned to the law. Through the influence of the
Duke of York and afterwards James II, ==Preservation==