According to the census in 1831, the population of Mentese was around 52,000. According to the archives, approximately 50,000 of these were Muslims and around 2,400 were non-Muslims (Greeks, Armenians, Jews). Most of the Muslim population were the Yuruks (the Turkmens). However it is also known that there was migration from Rumelia, Caucasia, Crete, and North Africa (Algeria, Tunisia and Egypt) because of various wars.
Mentese Bey (founder of Beylik of Mentese) was from Turkmen clans of Oghuz. The Beylik of Menteşe was ruled by the Great Seljuks State at Konya until 1308. It was also controlled by Ilkhanate State at Tabriz between 1308 and 1335. Finally they had their independence in 1335. The Beylik of Mentese continued to dominate the region from 1284 to 1390. It was contributed to the Ottomans territory in 1390 by Yıldırım Beyazıd. They announced their independence and separated from the Ottoman State in 1402 after Ankara Battle same as the others Anatolian Beyliks. However Mentese Beylik had to commit to the Ottoman State at the period of II. Murad once again. The capital town of Mentese Beylik was Milas. The Beys (the rulers) of Mentese Beylik used to settled down in Becin around Milas. They left important historical pieces on there.
With its powerful navy forces, they were a good example for the Ottomans to have and had lots of navy warfare made on the Aegean Islands and Greece. They even conquered some part of Rhodes Island. As Kanuni Sultan Suleiman conquered Rhodes and Bodrum in 1522, the knights had to run away to Malta. Menteşe became one of the 14 sanjaks(sub-province) of Anatolian Beylerbey (meaning Commander of Commanders) of Ottoman Empire at Kutahya (state capital) during Ottoman times. It became independent sanjak in 1867 and it called 'Mentese'.
The fertile lands of Mentese were rented to the noble people in the 18th century. Today, the local people over 70 years old come from Yuruk or African origins who are living in Bafa, Milas, Koycegiz narrate their hard lives of the dynasties that worked for peanuts at the tobacco fields belonging to their landlords and masters. After World War I, Italian forces invaded in Menteşe (1920-1921). Turkish National Force took over the control again in 1921. All sub-provinces in Anatolia became the province during the early period of the Turkish Republic. Before the Treaty of Lausanne, 92 % of Menteşe population was Turkish, 7% of it was Greek. The Greeks were sent to Greece according to the Treaty of Lausanne.