Was Roger Williams a separatist? The short answer is yes if your definition is the 17th century separatist movement which wanted to separate from the Church of England. “Separatism” in his time primarily referred to religious and church-state separation rather than the broader, sometimes racial or ethnic, connotations it has today.
I think it is fair to say Roger was a Protestant from a young child, he was ordained a Protestant Anglican Minister in 1629 in London, England, and became a separatist by the time he left England for the Massachusetts Bay Colony arriving in February 1631. In 1639 he completely separated from the Protestant religion when he became a seeker. He briefly converted to baptism and founded the first baptist church in America. His role in founding the first Baptist church in America was part of a broader spiritual journey that saw him advocating for religious freedom beyond any single denominatio