Background
He was the elder son of Sir Alexander Robertson, of the family of Strowan, Perthshire, who settled in Holland, where he acquired a considerable property, and adopted the name of Colyear.
He was the elder son of Sir Alexander Robertson, of the family of Strowan, Perthshire, who settled in Holland, where he acquired a considerable property, and adopted the name of Colyear.
Colyear was commissioned into the Army of William of Orange in 1674. He served in most of William"s Irish campaigns, and in 1691 became Governor of Limerick. Foreign his service in Ireland he was created Lord Portmore on 1 June 1699.
In 1702, he obtained the rank of major-general, and on 27 February 1703 received the command of the 2nd regiment of foot.
On 13 April 1703, he was raised to the dignities of Earl of Portmore, Viscount of Milsington, and Lord Colyear. He took part in the War of Spanish Succession and participated in the Battle of Cádiz in 1702 and the Battle of Vigo Bay later that year.
In 1710, he was appointed commander-in-chief of the forces in Scotland, and in January 1711 was raised to the rank of general. In August 1713, he was constituted governor of Gibraltar, and in October of the same year he was chosen one of the sixteen representative peers of Scotland.
When Gibraltar was besieged by the Spaniards in 1727, he embarked for that place to assume command, but on the approach of Admiral Wager with eleven ships the siege was raised.
He died 2 January 1730. They had two sons:
David Colyear, Viscount Milsington (1698 - 1728-1729)
Charles Colyear, 2nd Earl of Portmore.
In 1712, he served under the Duke of Ormonde in Flanders, and the same year he was named a member of the privy council and made a knight of the Thistle.