Laski, John (lăsˈkē) [key], Pol. Jan Łaskiyän lăsˈkē, Latin Johannes Alasco, 1499–1560, Polish Protestant reformer. A learned priest, he went in 1523 to Basel, where he was a close friend of Erasmus. After returning to Poland he rose to archdeacon of Warsaw, but because of his Calvinistic views he had to leave. He became pastor of a Protestant church at Emden in 1542 and shortly after went to England, where in 1550 he was superintendent of the church for Protestant foreigners and had some influence on ecclesiastical affairs in the reign of Edward VI. On the accession of the Roman Catholic Queen Mary he fled to the Continent. In 1556 he was recalled to Poland, where he was secretary to King Sigismund II and was a leader in the Calvinistic Reformation.