Conquest of Yenişehir and Its Surroundings After securing his northern borders by reaching the Black and Marmara seas, Osman turned his attention towards the southern borders of his beylik. Thus, he attacked the Byzantine towns, villages, and fortresses surrounding the city of Yenişehir preparing to conquer it. Osman sent a large campaign to the fortress of Yāvandhisar and annexed it. Then, he attacked Yenişehir, took it with ease, and made it his temporary capital after fortifying and strengthening its defenses. Soon after that Osman started sending more campaigns against the remaining Byzantine cities conquering several fortresses including Lefke, Akhisar, Koçhisar, Yenicehisar, Marmaracık, and Köprühisar. In fact, conquering the aforementioned forts aimed at imposing a security belt around Yenişehir, thus Osman surrounded it with a series of front forts to ward off any invasions.
conquest of yenişehir and its surroundings after securing his northern borders by reaching the black and marmara seas osman turned his attention towards the southern borders of his beylik thus he attacked the byzantine towns villages and fortresses surrounding the city of yenişehir preparing to conquer it osman sent a large campaign to the fortress of yāvandhisar and annexed it then he attacked yenişehir took it with ease and made it his temporary capital after fortifying and strengthening its defenses soon after that osman started sending more campaigns against the remaining byzantine cities conquering several fortresses including lefke akhisar koçhisar yenicehisar marmaracık and köprühisar in fact conquering the aforementioned forts aimed at imposing a security belt around yenişehir thus osman surrounded it with a series of front forts to ward off any invasions