Thomas and Alexander Campbell and Barton Stone were all ex-Presbyterian ministers who had been influenced by reformers in Scotland, specifically John Glas, Robert Sandeman (Glas's son-in-law) and Robert and James Haldane. Glas (1695-1793) became known as the founder of the 'Scotch Baptists' becaused they practised adult baptism by immersion. An ordained minister in the Presbyterian church, Glas was determined early on to make the Word of God his sole rule of conduct. When he began preaching a series of lessons from the Shorter Catechism (Presbyterian Manual) he noted there were strong differences in it from the Bible.
He came to realise that the church was composed of those who had experienced the grace of Christ, had separated themselves from the world and gathered themselves in the church.
His teaching was regarded as close to treason
Sandeman migrated to North America where he established a church which later joined the Restoration Movement.