Kyrillos Loukaris or Cyril Lucaris (1572–June 1638; Greek Κύριλλος Λούκαρις or Λούκαρης) was a Greek prelate and theologian, and a native of Candia, Crete (then under the Republic of Venice). He later became the Greek Patriarch of Alexandria as Cyril III and Ecumenical Patriarch of Constantinople as Cyril I. Loukaris strove for a reform of Orthodoxy along Protestant and Calvinist lines but was opposed both from within his own communion and by the Jesuits. He was the first great name in the Eastern Orthodox Church since the fall of Constantinople in 1453, and dominated its history in the 17th century.