The princely houses of Poland and Lithuania differed from other princely houses in Europe. Most importantly, Polish nobility (szlachta) could not be granted nobility titles by the Polish kings in the Polish-Lithuanian Commonwealth. Therefore, the title of prince either dated to the times before the Union of Lublin, which created the Commonwealth in 1569, or was granted to some nobles (usually magnates) by foreign kings. Due to the longstanding history of common statehood, some noble families often described as "Polish" actually originated in Grand Duchy of Lithuania and are of Lithuanian or Ruthenian descent. Some houses are more correctly described as being of Polish-Lithuanian Commonwealth.