Zeybeks, sometimes spelled as Zeibeks ( Zeibekoi; ), were irregular militia and guerrilla fighters living in West Anatolia from late 17th to early 20th centuries. History The origins of Zeybeks are debated with most Turkish sources supporting that they are Turkic. One Turkish source states the Zeybeks first appeared in the 13th century and were Turkmens who settled into the Aegean Region. Another Turkish source links them to the Turkmen-Celali rebels in the 16th century, while a different Turkish writer claims that Zeybeks were light infantry troops made of Turkmen tribes loyal to the Seljuks. According to Aşıkpaşazade, an Ottoman Turkish Historian from the 15th century, Zeybeks were Muslim Gazis 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. Ottoman Turkish author Osman Hamdi Bey supports that they were descendants of the Trallians and unrelated to the Turks. However, according to other sources, mostly Greek, the Zeybeks were of Greek origin. According to Greek historian Kostas B. Spanos, the Zeybeks were Greeks who migrated from Thrace and settled in Bursa, Aydin and Sakarya. They were Islamized but not Turkified. According to another Greek historian, Georgios Skalieris, they were of Greek and Phrygo-Pelasgian descent. Greek historian Thomas Korovinis, in his detailed study of the Zeybeks, summarizes 7 of the main theories on their origins. These posit that the Zeybeks are the descendants of: 1) Turkomans and Yoruks 2) Levantines 3) Ancient Anatolians. 4) Ephesians, Ionians and Lydians. 5) Graeco-Phrygians (see Graeco-Phrygian languages). 6) Greeks and Thracians. 7) Trallians and neighboring nomads, such as the Yoruks. Traditionally, the Zeybeks 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 (efevos, 'young man with courage') or Turkic (eğe, ece, ebe, "big brother" in old 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, soldiers"