The Sejm (English: , Polish: ), officially known as the Sejm of the Republic of Poland (Polish: Sejm Rzeczypospolitej Polskiej), is the lower house of the bicameral parliament of Poland. The Sejm has been the highest governing body of the Third Polish Republic since the transition of government in 1989. Along with the upper house of parliament, the Senate, it forms the national legislature in Poland known as National Assembly (). The Sejm is composed of 460 deputies (singular deputowany or poseł – "envoy") elected every four years by a universal ballot. The Sejm is presided over by a speaker called the "Marshal of the Sejm" (Marszałek Sejmu). In the Kingdom of Poland, the term "Sejm" referred to an entire two-chamber parliament, comprising the Chamber of Deputies (), the Senate and the King. It was thus a three-estate parliament. The 1573 Henrician Articles strengthened the assembly's jurisdiction, making Poland a constitutional elective monarchy. Since the Second Polish Republic (1918–1939), "Sejm" has only referred to the lower house of parliament. History Kingdom of Poland Sejm (an ancient Proto-Lechitic word meaning "gathering" or "meeting") traces its roots to the King's Councils – wiece – which gained authority during the time of Poland's fragmentation (1146-1295). The 1180 Sejm in Łęczyca (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 was also established; the Sejm then comprised two chambers: the Senat (Senate) of 81 bishops and other dignitaries; and the Chamber of Deputies, made up of 54 envoys elected by smaller local sejmik (assemblies of landed nobility) in each of the Kingdom's provinces. At the time, Poland's nobility, which accounted for around 10% of the state's population (then the highest amount in Europe), was becoming particularly influential, and with the eventual development of the Golden Liberty, the Sejm'''s powers increased dramatically. Polish–Lithuanian Commonwealth Over time, the envoys in the lower chamber grew in number and power as they pressed the king for more privileges. The Sejm eventually became even more active in supporting the goals of the privileged classes