In 1230 the Knights of the Teutonic Order built a castle near the city of Torun, located on the Vistula River. The city was granted city rights in 1233, and in 1264 the New Town was founded to the east of the Old Town. Torun became an important commercial center as a member of the Hanseatic League. In 1454 the citizens of Torun rised up against the Knights of the Teutonic order and destroyed the castle. The city then became part of the Kingdom of Poland. The great astronomer Nicolaus Copernicus (1473-1543), founder of the heliocentric theory (where the Sun is the center of the solar system instead of the Earth) was born in Torun where he spent his young years. In 1793 Torun became part of the Kingdom of Prussia until World War I when it became again part of Poland.