The szlachta (, ) was a privileged social class in the Kingdom of Poland. The term szlachta was also used for the Lithuanian nobility after the union of the Grand Duchy of Lithuania with Poland as the Polish–Lithuanian Commonwealth (Union of Lublin, 1569) and for the increasingly Polonized nobilities of territories controlled by the Polish–Lithuanian Commonwealth, including Ducal Prussia and the Ruthenian lands. The Polish–Lithuanian Commonwealth was a semi-confederated, semi-federated monarchic republic from 1569 until 1795, comprising the Kingdom of Poland and the Grand Duchy of Lithuania. The head of state was an elected monarch. The Commonwealth's dominant social class was the nobility. This article chiefly lists the nobility's magnate segment (the wealthier nobility), as they were the most prominent, famous, and notable. These families would receive non-hereditary 'central' and Land dignities and titles under the Commonwealth law that forbade (with minor exceptions) any hereditary legal distinctions within the peerage. They would later be 'approximated' to honorary hereditary titles in the Partition period with little real-power privileges but would still be venerated among the Polish upper class and the rest of the society as 'senatorial', 'palatinal', 'castellanial' or "dignitarial' families. "Szlachta" is the proper term for Polish nobility beginning about the 15th century. Most powerful members of szlachta were known as magnates ("magnaci" or the "magnateria" class). A Polish nobleman who lived earlier is referred to as a "rycerz" ("knight"); the class of all such individuals is the "rycerstwo" (the "chivalry" class). Most powerful members of "rycerstwo" were known as "możnowładcy" (the "moznowładztwo" class). By family Below is a list of most important Polish noble (szlachta) families. The families listed are the famous magnates families - ones that had accumulated great wealth and political power, generally preserved across several centuries. Please note that this list is not intended to be a comprehensive list of all szlachta families. For the list of lesser known but still notable Polish noble families, see the corresponding category All names are given first in the singular, then (parenthetically) in the plural. Borkowski (Borkowscy) Chodkiewicz (Chodkiewiczowie) Czartoryski (Czartoryscy) Gorczewski (Gorczewscy) Lanckoroński (Lanckorońscy) Litwicki (Litwiccy) Lubomirski (Lubomirscy) Mielzynski (Mielzynscy) . Ogiński (Ogińscy) Ostrogski (Ostrogscy) Ostroróg (Ostrorogowie) Pac (Pacowie) Poniatowski (Poniatowscy) Potocki (Potoccy) Radziwiłł (Radziwiłłowie) Sapieha (Sapiehowie) Sanguszko (Sanguszkowie) Tarnowski (Tarnowscy) Tęczyński (Tęczyńscy) Tyszkiewicz (Tyszkiewiczowie) Wiśniowiecki (Wiśniowieccy) Zamoyski (Zamoyscy) Żeleński (Żeleńscy) By year of birth Listed below are prominent szlachta of Poland and the Grand Duchy of Lithuania,