The tangible legacy of liberation historical geography of the Ertugrul and Osman Gazi periods

Ertuğrul Gazi's ancestors, the Kayı tribe, along with other migrating Turkic tribes, initially settled near Khorasan, Merv, and Mahan. Due to increasing Mongol pressure, the Kayı migrated to Eastern Anatolia and around Aleppo, where they lived for a time. Later, the Kayı tribe split in two; one part headed towards Khorasan, while the others migrated to the Sürmeli valley region of Erzurum. Afterward, arriving in the Karacadağ region of Ankara, the Kayı, under the leadership of Ertuğrul Gazi, lived there for a while before Sultan Alaeddin I granted them the Söğüt-Domaniç region as their homeland, settling in the area we call the Ottoman founding geography. During his reign, Ertuğrul Gazi maintained a policy of compromise with the local Byzantine lords; after his death, his son Osman Gazi succeeded him as bey. Osman Gazi, for a time, continued his father's policy of compromise with the local lords, but this policy soon gave way to ghazawat (holy war) and conquest. Having conquered Karacahisar in 1287-88, by 1299 Osman Bey had captured important Byzantine territories such as Bilecik, Köprühisar, Yarhisar, and İnegöl. Furthermore, in 1302, he fought and won two important battles against the Byzantines, at Bafeus and Dinboz, consolidating his dominance in the region. The Sakarya campaigns took place in 1304-1305, resulting in Ottoman victories. Most of the struggles during Osman Gazi's reign served as preparation for the conquest of İznik and Bursa. The doctoral thesis titled The Tangible Legacy of Liberation Historical Geography of the Ertugrul and Osman Gazi Periods aims to reveal the present-day locations of settlements, roads, castles, and villages mentioned in the sources by reading the Ertuğrul and Osman Gazi periods through historical chronicles.