Michael Servetus Michael Servetus (1509 or 1511-October 27, 1553), a Spaniard martyred in the Reformation for his criticism of the doctrine of the trinity and his opposition to infant baptism, has often been considered an early unitarian. Sharply critical though he was of the orthodox formulation of the trinity, Servetus is better described as a highly unorthodox trinitarian. Still, aspects of his theology—for example, his rejection of the doctrine of original sin—did influence those who later founded unitarian churches in Poland and Transylvania. Public criticism of those responsible for his execution, the Reform Protestants in Geneva and their pastor, John...