Socinus, Laelius (Lelio Sozzini), a noted Italian heresiarch, uncle of the preceding, was born in Sienna in 1525, being the son of Mariano Sozzini, Jun., a lawyer, of a family that made considerable pretensions to learning. Lelio gave himself to the study of theology, then quickened by the discussions of Luther, and for this purpose read the Bible in the original tongues. This made him suspected by the Church authorities, and he left Italy about 1544, and wandered for four years over France, England, the Netherlands, and Germany in search of knowledge. He at last settled at Zurich, where his erudition and personal qualities at first gained him consideration, and there entered upon a series of investigations and a course of correspondence which resulted in undermining his belief in the divinity of Jesus Christ. These convictions rendering him unpopular at Zurich, he retired, after the death of his father, in 1558 or 1559, to Poland, where Sigismund II received him favorably, and gave him letters that enabled him to return with prestige to Zurich; and he spent the remainder of his days there in peace, dying May 16, 1562. He left the following works: Dialogus inter Caivinum et Vaticanum (s.l. 1612, 8vo), in which he opposes the punishment of heretics: — De Sacramemis and De Resurrectione Corporum, both inserted in Fausti et Loelii Socini Tractatus (Eleutheropolis [Holland], 1654). Sand (Biblioth. Antitrin. p. 18-25) speaks of some other doubtful writing attributed to Laelius Socinus.