Laelius Socinus (lē´lēəs sōsī´nəs) or Lelio Sozzini (lā´lyō), 1525–62, Italian religious reformer. After becoming interested in Protestantism, Socinus left Italy in 1544 for the Swiss cantons to escape the newly established Inquisition. He had been attracted by the writings of Martin Luther, and during his wide travels he met many leaders of the Reformation. In Switzerland, Heinrich Bullinger became his good friend. John Calvin, however, suspected Socinus of doctrinal differences, and to allay these suspicions Socinus signed a confession of faith in 1555. However, there seems reason to believe that the burning of the anti-Trinitarian Servetus in 1553 and Socinus's friendship with Bernardino Ochino had led him to entertain private anti-Trinitarian views. The writings of Socinus, left to his nephew Faustus Socinus, were used in the development of Socinianism.