Thomas Helwys (c. 1550-c.1616), the founding father of the Baptist movement was an Arminian. His well known ministry partner John Smyth eventually fell away from his Arminianism into heresy. The Baptist movement was entirely Arminian for a generation before any Calvinist Baptists arrived anywhere on the scene.
Roger Williams (1603-1683) established the first Baptist church in America. While parting ways with the Baptists shortly afterwards, at the time when the church was established, he held to a general view of the atonement. The church later succombed to Calvinistic pressures, resorting to the view that Jesus only died for the few who were predetermined.