The Sack of Sandomierz took place on 13 February 1241 in the Polish city of Sandomierz, during the first Mongol invasion of Poland. It ended in the victory of the Mongol forces, who captured the city and burned it, massacring the residents. During the Mongol invasion of Poland, southeastern Polish city of Sandomierz was regarded by the invaders as a strategically important location, which had to be captured. Sandomierz lies near the confluence of the Vistula and the San rivers, near the 13th-century border between the Kingdom of Poland and Mongol-controlled Red Ruthenia.