By whom and when was the Ottoman Empire discovered?

The founding of the Ottoman Empire took place in 1299 during the reign of Osman 1, who actively conquered the territories of Byzantium. So no one had to open the Ottoman state, as it had long been known about it, including the Byzantine emperors, who tried their best to prevent the collapse of their empire. Yet the power of Byzantium was finally undermined. At that time, it lost most of its territories, and in 1453 Constantinople itself fell, which became the new capital for the Ottoman Empire.