John Smyth was an English theologian and a key figure in the early development of the Baptist movement in the early 17th century. He is best known for his role in founding the first Baptist church in Amsterdam in 1609, where he advocated for believer's baptism and religious freedom. Smyth's writings emphasized the importance of personal faith and the authority of the Bible. Smyth's theological views were influenced by his experiences in the Separatist movement, which sought to break away from the established Church of England. He later became a proponent of congregational governance, where each church is self-governing. His contributions laid the groundwork for future Baptist leaders and the broader Protestant Reformation.