Sect leader. Born in Perth, Sandeman was educated at the University of Edinburgh. He joined the Glassites, who practised a simple and literal form of Christianity, and in 1737 married the daughter of their leader, John Glass (1695 - 1773). His controversial Letters on Theron and Aspasio were published in 1757. Having moved to London in 1760, Sandeman developed the Glassite philosophies in England, where his followers became known as Sandemanians. Having heard that this work had been well-received in the American colonies, Sandeman set sail in 1764 and settled in Danbury (Connecticut). There he preached his bare faith in various towns, resulting in a number of new churches being formed.
He died in Danbury, having had a significant influence on later preachers such as Greville Ewing (1767 - 1841) and is buried in that town.