||Andreas Osiander (Andreas Hosemann) (Ansbach, Bavaria, 19 December 1498 – 17 October 1552 in Königsberg, Prussia) was a German Lutheran theologian. Born Andreas Hosemann in the town of Ansbach, Osiander studied in Leipzig, Altenburg and Ingolstadt before being ordained as a priest in 1520. In the same year he began work at an Augustinian convent in Nuremberg as a Hebrew tutor. In 1522, he was appointed to the church of St. Lorenz in Nuremberg, and at the same time publicly declared himself to be a Lutheran. During the First Diet of Nuremberg (1522), he met Albert of Prussia, Grand Master of the Teutonic Knights, and played an important role in converting him to Lutheranism. He also played a prominent role in the debate which led to the city of Nuremberg's adoption of the Reformation in 1525, and in the same year Osiander married.
Osiander attended the Marburg Colloquy (1529), the Diet of Augsburg (1530) and the signing of the Schmalkalden articles(1531). The Augsburg Interim of 1548 made it necessary for him to leave Nuremberg, settling first at Breslau, then (in 1549, at Königsberg as professor of the newly founded Königsberg University, appointed by Albert of Prussia. Osiander lived and worked in Königsberg until his death in 1552. Osiander's son Lukas (1534-1604), and grandsons Andreas (1562-1617) and Lukas (1571-1638) also worked as theologians.
Osiander published a corrected edition of the Vulgate Bible, with notes, in 1522 and a Harmony of the Gospels in 1537. In 1533, Brandenburg-Nuernbergishe Kirchenordnung vom Jahre 1533 was published, with Osiander assisting in both the source material the final editing. This combined order of worship and catechism was the first work to include the Keys section of Luther's Small Catechism, of which Osiander is a suspected author. In 1543, Osiander oversaw the publication of the book De revolutionibus orbium coelestium (On the revolution of celestial spheres) by Copernicus, and added an unsigned preface explaining that the model described in the book was not intended as a description of the way the Universe really is, but as a mathematical device to simplify calculations involving the movement of planets. In 1550 Osiander published two controversial disputations, De Lege et Evangelio and De Justficatione. In these, he set out his view that justification by faith was instilled in (rather than ascribed to) humanity by Christ's divinity, a view contrary to those of Martin Luther and John Calvin although he agreed with Lutheranism's fundamental opposition to Roman Catholicism and Calvinism. These beliefs were maintained after his death by Johann Funck (his son-in-law) but disappeared after 1566.
In 1529, Andreas Osiander authored a tract, published anonymously in 1540, that systematically and forcefully refuted the charge of Jewish ritual murder of Christian children. Osiander was a Christian Hebraist who engaged in the study of Cabbala and had a thorough knowledge of rabbinic literature and the Talmud. He argued that it is “inconceivable that the Jews should murder children and make use of their blood” when their own Kosher laws forbade them even to eat the meat of animals containing blood. The treatise appeared just as the investigation of one such supposed murder at Tittingen was ongoing.