Osiander, ANDREAS, German reformer, was born on 19th December 1498, at Gunzenhausen, near Nuremberg. His name is a Græcised form of the original German Heiligmann or Hosemann. Educated at Ingolstadt, he declared himself an adherent of Luther, and became a preacher at Nuremberg (1522), persuaded that city to declare itself Lutheran, took part in the conference at Marburg (1529), and was present at the diet of
Augsburg (1530), and at the signing of the Schmalkalck articles (1537). In 1548 he was deprived of his office as preacher because he refused to agree to the Augsburg Interim; but was immediately afterwards invited by Albert, Duke of Prussia, to become professor of Theology in the newly-established university of Königsberg. He was hardly settled there when he became entangled in a theological strife that was greatly embittered by his vehement and arrogant temper. In a treatise, De Lege et Evangelio, Osiander asserted that the righteousness by which sinners are justified is not to be conceived as a mere justificatory or imputative act on the part of God, but as something inward and subjective, springing in a mystical way from the union of Christ with man. The most notable of his opponents was Martin Chemnitz (q.v.). Osiander's death in the midst of this fierce polemical war, on 17th October 1552, did not check it; the battle was continued by his followers, called Osiandrists, and led by his son-in-law Funk, who was executed for high-treason in 1566, and the entire party was banished from Prussia in 1567. See Lives by Wilken (1844), Möller (1870), and Hase (1879). Osiander's son Lukas (1534-1604) and his son Lukas (1571-1638) won reputations as theologians of note.