Michael Servetus
Michael Servetus (1511-1553) was a polymath or Renaissance man who not only denied the Trinity but discovered the workings of the human pulmonary circulatory system in his spare time. He’s considered to be an early Unitarian because of his anti-Trinitarian views, but he was certainly a (heretical) Christian long before the modern idea of Unitarianism came about. Out of the Flames is a thrilling but accurate story of his life, well worth the read. It’s available at the Toronto library.