Career
William Cochrane of Coldoun, who was knighted by Charles I, acquired the estate of Dundonald in 1638. He was created Baron Cochrane of Dundonald in 1647. The part he had taken in the Wars of the Three Kingdoms, is evidenced by the proceedings of the Presbytery of Ayr, who, on 28 February 1649, debarred "Lord Cochrane" from renewing the Solemn League and Covenant, he having "been a Colonel in the late unlawful rebellion, and having went to Ireland to bring over forces," et cetera
In 1654, he was fined in £5,000 by Cromwell"s Acting of Grace and Pardon.
In 1669, he was made a Commissioner of the Treasury and Exchequer, and created Baron Cochrane, of Paisley and Ochiltree (having previously acquired the latter barony), and Earl of Dundonald, with remainder to the heirs-male of his body, failing which, to tho eldest heirs-female of his body without division, and the heirs-male of such heirs-female, bearing the name and arms of Cochrane. The Earl died in 1686, and was interred in the church of Dundonald.
William Cochrane married Eupheme, daughter of Sir William Scott of Ardross and Elie, county of Fife, and had issue:
William, Lord Cochrane, who died, during the life of his father, in 1679, leaving issue by Katherine, daughter of John Kennedy, 6th Earl of Cassillis,
John, 2nd Earl of Dundonald (c 1660–1690)
William, of Kilmaronock, died 1717, having married Grizel, daughter of James Grahame, 2nd Marquis of Montrose, and had issue, Thomas, 6th Earl. Sir John, of Ochiltree, from whom Thomas, the eighth Earl was a descendant.
Margaret, married, in 1676, to Alexander, 9th Earl of Eglinton, and had issue.
Helen, married to John, 15th Earl of Sutherland, and had issue. Jean, married, first to John, 1st Viscount Dundee. Secondly, to William, 3rd Viscount of Kilsyth, and had issue.
Grizel, married George Ross, 11th Lord Ross.