Zeybeks or sometimes Zeibeks, were irregular militia and guerrilla fighters living in the Aegean Region of the Ottoman Empire from late 17th to early 20th centuries. Their origins are debated. According to Greek sources, Zeybeks were Islamized Greeks, while Turkish sources claim that they are Turkic. One source states the Zeybeks first appeared in the 13th century and were Turkmens who settled in to the Aegean region. Another source links them to the Turkmen-Celali rebels in the 16th century, while a different writer claims that Zeybeks were light infantry troops made of Turkmen tribes loyal to the Seljuq Empire According to Aşıkpaşazade, an Ottoman Historian from the 15th century, Zeybeks were MuslimGhazis protecting the borders in Anatolia. In the Turkish society the Zeybeks and Yörüks are seen as the same people. Many famous Zeybeks like Yörük Ali Efe and Demirci Mehmet Efe belonged to Yörük tribes. Traditionally, they acted as protectors of village people against landlords, bandits and tax collectors. A leader of a Zeybek gang was called Efe and his soldiers were known as either Zeybeks or Kızan. The term "Efe" was used for the leaders of Zeybek groups, while the "Kızan" were beneath the Zeybeks. According to the Armenian-Turkish linguist Sevan Nisanyan, the origin of the term "Efe" is either of Greek or Turkic origin. The origin of the term "Zeybek" is according to Nisanyan also not clear. According to Nisanyan it is either of Turkic or Arabic origin Some sources claim that it evolved from "Sübek", "Sü" meaning army and soldiers and "Bek" meaning lord in old Turkic. According to Onur Akdogu it evolved from "Saybek", meaning "Strong Guardian" in old Turkic. According to Paul Wittek it may evolved from the name "Salpakis Mantachias" used by the Byzantine historian Pachymeres for MenteshBey, who founded the Beylik of Menteşe in southwestern Anatolia. The term "Kızan" is of Turkic origin and means "boy". Kızan was generally used for newly recruited or inexperienced Zeybeks. There was generally a tribe democracy within a group. Decisions were made in a democratic way and after the decision was made, Efe had an uncontroversial authority. They followed definite rituals for all actions; for example, the promotion of a kızan to zeybek was very similar to Ahi rituals. From the 17th to 19th century, the Zeybeks evolved to outlaws and bandits terrorizing the Aegean Region. Before the Treaty of Lausanne and the establishment of the Republic of Turkey, larger concentrations of Zeybeks could be found on the Aegean coast of western Anatolia, near the city ofİzmir and Magnesia. After the Greek landing at Smyrna they fought against the Greek occupation of western Turkey. Following the formation of a Turkish national army, during the Greco-Turkish War of 1919–1922, most of them joined the regular forces and continued their resistance. During and after the Turkish War of Independence they were no longer seen as bandits and outlaws, but as heroes, nationalist forces fighting against a foreign and non-muslim force. An English report about the Zeybeks and Yörüks states; "Those people hate the Greeks, and are known for their heroism." Zeybeks have a dance called the Zeybek dance in which performers simulated hawks. There are different Zeybek dances in Turkey. There is the "Avşar Zeybeği", Aydın Zeybeği, Muğla Zeybeği, Tavas Zeybeği, Kordon Zeybeği, Bergama Zeybeği, Soma Zeybeği, Ortaklar Zeybeği, Pamukçu Zeybeği, Harmandalı Zeybeği, Sakız Zeybeği, Tefenni Zeybeği, Kadıoğlu Zeybeği, Kocaarap Zeybeği, Abdal Zeybeği and Bengi Zeybeği. The Greeks used to call the Zeybek dance "Türkikos", but this name is not used anymore. Romantic songs about their bravery are still popular in Turkish and Greek folk music. The yatagan sword was their primary weapon, but most of them carried firearms as well.