1485-1553. Dominican theologian and archbishop of Conza. Born at Siena with the name of Lancelotto Politi, he studied both canon and civil law before receiving a doctorate. Influenced by Savonarola,* he entered the Dominican House of San Marco at Florence in 1517, taking the name Ambrosius Catharinus (from the two names Ambrosius Sansedoni and St. Catherine). He wrote against Luther in 1520 with Apologia Pro Veritate Catholicae Ac Apostolicae Fidei. Luther responded with Ad Librum A. Catharinii Responsio, to which Catharinus replied with Excusatio Disputationis contra Lutherum. Later he even wrote against a fellow Dominican, Cardinal Cajetan*; this book, Annotationes, defended the doctrine of the . Another object of his literary skill was , the friend of . While living in France he published his Opuscula Magna (1542), which revealed that he was not afraid to deviate from Dominican orthodoxy on matters such as predestination, original sin, the Virgin Mary, etc. After taking a prominent part in the * he was made bishop of Minori in 1546 by Paul III and archbishop of Conza by in 1552.