Polish heraldry is the study of the coats of arms that have historically been used in Poland and the Polish–Lithuanian Commonwealth. It treats of specifically Polish heraldic traits and of the Polish heraldic system, contrasted with heraldic systems used elsewhere, notably in Western Europe. Due to the distinctive ways in which feudal societies evolved. Poland's heraldic traditions differ substantially from those of the modern-day German lands and France. Polish heraldry is an integral part of the history of the Polish szlachta (nobility). History Unlike Western Europe, in Poland, the Polish nobles did not emerge exclusively from the feudal class of knights but stemmed in great part from earlier Slavic local rulers and free warriors and mercenaries. Rulers often hired these free warriors and mercenaries to form military units () and eventually, in the 11th century during the time of Casimir I the Restorer with the development of feudalism, armies paid by the Prince were replaced by knights that were paid in land. Much written evidence from the Middle Ages demonstrates how some elements of the Polish nobility did emerge from former Slavic rulers that were included in the ranks of the knightly class under the terms of the chivalric law () and . Because Polish clans () have different origins, only part of the szlachta can be traced all the way back to the traditional old clan system based on kinship. The clans that could show kinship belonged to a House (), such as the House of Odrowąż. Later, when different Houses created different surnames for each property, the House turned into the Clan Odrowąż. Other szlachta were not related and their unions were mostly voluntary and based on fellowship and brotherhood rather than kinship, still being full members of the Clan, creating Clan politics like in Clan Ostoja or Clan Abdank, but forming a heraldic clan. Near the end of the history of the Polish–Lithuanian Commonwealth, due to adoptions and other circumstances, all Clans in Poland turned into Heraldic Clans. In the year 1244, Bolesław, Duke of Masovia, identified members of the knights' clan as members of a genealogia: I received my good servitors [Raciborz and Albert] from the land of [Great] Poland, and from the clan [genealogia] called Jelito, with my well-disposed knowledge [i.e., consent and encouragement] and the cry [vocitatio], [that is], the godło, [by the name of] Nagody, and I established them in the said land