(known as the 'First Polish parliament') was the most notable, in that it established laws constraining the power of the ruler. It forbade arbitrary sequestration of supplies in the countryside and takeover of bishopric lands after the death of a bishop. These early Sejms only convened at the King's behest.

Following the 1493 Sejm in Piotrków, it became a regularly convening body, to which indirect elections were held every two years. The bicameral system