Puritan Minister. Born in Elie (Fife), Traill's father had been Minister at Greyfriars Church in Edinburgh and had been one of the first to sign the National Covenant in 1638. Traill was educated at the University of Edinburgh but his father was forced to leave Scotland at the Restoration (1660). The young Traill was a supporter of Rev. James Guthrie and attended him at his execution in 1661. He was an enthusiastic supporter of the Covenanting cause and was forced into hiding in 1666. He was present at the Pentland Rising at Rullion Green in the same year, and with the Covenanters routed, fled to the Netherlands where he joined his father and began writing. In 1669, he moved to London and began preaching there. In 1677 he visited Edinburgh and was arrested, tried and imprisoned for some months on the Bass Rock (East Lothian). After his release, he returned to London where he remained until his death.