The accession of the Piast Duke Władysław I the Elbow-high ends the power struggle amongst the Polish nobility.

He unites the various principalities of the Kingdom of Poland, and in 1320 he is crowned King.

His son Casimir III the Great greatly strengthens the Polish state in both foreign and domestic affairs.Casimir is the last male member of the Piast dynasty and is succeeded by his nephew, Louis I of Hungary from the Angevine dynasty.

The upsurge of the monarchy continues under Louis, during the union of Hungary and Poland.Since Louis has no son either, his daughter Jadwiga becomes the heir of the Polish monarchy.

Under the terms of the Union of Krewo, she marries Jogaila, Grand Duke of Lithuania, who converts to Christianity.

This marriage creates not only a dynastic union between Poland and Lithuania but also binds the two countries together for the next four centuries.