The Orthodox clergy of Ruthenia, annexed to Poland in 1569, drew up at Brest, June 24, 1590, a document by which they submitted themselves to the jurisdiction of the pope on condition that their Eastern rites and liturgical customs were to be preserved. The union of the Ruthenian Church with the Church of Rome was solemnly proclaimed, October 9, 1596, after receiving the approbation of Clement VIII and King Sigismund of Poland.