David Quidnunc • Link
Henry Isham was the brother of Edward Mountagu's stepmother, Ann, who married Sidney Mountagu in 1644.
He lived most of his life in the Canary Islands and in Portugal. By 1657, when he was about 64, he was serving under Mountagu, probably as a volunteer in the navy.
-- Latham & Matthews edition of the diary, Companion volume (10).