Haşim Şahin, Dervişler, Fakihler, Gaziler, Erken Osmanlı Döneminde Dinî Zümreler (1300-1400), YKY Yayınları, İstanbul, 2020.

After the 1243 Kosedag war, the fall of the Anatolian Seljuk State had begun. The areas under his rule came under the influence of the Mongols. Since the extremes were relatively far from this influence, independent principalities emerged there. One of them was the Ottoman Principality. The Ottomans, who had the opportunity to expand especially in the Marmara region, expanded their domains by opening up to Rumelia. With the expansion and strengthening of the state, scholars, Sufis, and veterans from different regions of the Islamic geography migrated to the regions where the Ottoman rule was. Thus, the Ottomans with the accumulation of people from different lands; were fed culturally, religiously, administratively, militarily, and intellectually. Hasim Şahin states that the lack of "detailed studies on social factors understood to have an important role in the formation of the Principality" is a factor in the emergence of this study. In this study, the related work has been examined.