sentences:  Lublin is the largest Polish city east of the Vistula River and is about to the southeast of Warsaw by road.One of the events that greatly contributed to the city's development was the Polish-Lithuanian Union of Krewo in 1385.Lublin thrived as a centre of trade and commerce due to its strategic location on the route between Vilnius and Kraków; the inhabitants had the privilege of free trade in the Grand Duchy of Lithuania.