Unions of Lublin and Brest

The Union of Lublin, signed in 1569, was a significant agreement that united the Kingdom of Poland and the Grand Duchy of Lithuania into a single, integrated state called the Polish-Lithuanian Commonwealth. This union aimed to strengthen political and military cooperation, creating a more balanced and powerful entity in Eastern Europe. The Union of Brest, signed in 1596, was an agreement that brought some Eastern Orthodox Christians within the Polish-Lithuanian Commonwealth into communion with the Roman Catholic Church, establishing the Greek Catholic (or Eastern Catholic) Church. It sought religious unity while preserving Eastern Christian traditions within a Catholic framework.