Polish–Lithuanian Commonwealth 1500 CE, known as Kingdom of Poland and Grand Duchy of Lithuania (Federation of Poland and Lithuania) ruled by common monarch in real union, who was both King of Poland and Grand Duke of Lithuania.

It was one of largest and most populous countries of 16th-17th Century, Europe. Its largest territorial extent in early 17th Century CE, Commonwealth covered 400,000 sq mi. In 1618, a multi-ethnic population of 12 million. Polish and Latin were co-official languages.