Polish–Lithuanian Commonwealth
The Polish–Lithuanian Commonwealth, formally known as the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania and, after 1791, the Commonwealth of Poland, was a state of Poland and Lithuania that was ruled by a common monarch. The Commonwealth was an extension of the Polish-Lithuanian Union, a personal union between those two states that had existed from 1386. It was the largest and countries of 16th- and 17th-century Europe and had one of the largest populations. The Polish–Lithuanian Commonwealth covered more lands than the present lands of Poland and Lithuania since it covered also all of present-day Belarus, a large part of present-day Ukraine and Latvia, and the west of present-day Russia.