In 1608, John Smyth baptized himself in Amsterdam. He had been a fellow of Christ's College, Cambridge, but as a Separatist fled from the harsh rule of James I's England. After his death one of his associates, Thomas Helwys, led back to England a group that had split from Smyth's former congregation. They formed the first General or Arminian Baptist congregation in England at Spitalfields, London, in 1612.

By 1638 at the latest there were also congregations holding a Calvinistic theology in London who practiced believers' baptism ("Particular Baptists"). These Baptists grew out of the first congregation of English Independents; although it is not know exactly when they adopted full Baptist views. A radical look at church principles, in the Puritan manner, led first to the understanding of the church as a gathered community, and then to a realization that only the baptism of believers fitted such a view.

After the Hampton Court Conference, little groups of believers began to meet for worship as they felt the Bible taught them — not according to bishops and prayer books. This movement was identified as separatism because the groups were intent upon leaving the Church of England. One of these groups was in Gainsborough in northern England. By 1608 this group had moved to Amsterdam, Holland for safety and freedom of worship. John Smyth was the pastor of this flock. A Cambridge graduate, he studied his Greek New Testament with care and discovered that the practice of baptizing babies never appeared in its pages. If babies were not included in the covenant of grace — only mature believers in Jesus Christ — then shouldn't churches be constituted by confession of faith rather than ties of covenants? Smyth and forty members of the Amsterdam congregation answered, "yes", and were baptized upon the profession of their