Osman I, a tribal leader, was the key figure behind the establishment of the Ottoman Empire around the late 13th century. He founded the dynasty that would grow into one of the most powerful empires in history. Under his leadership, Islamic states began to consolidate power in Anatolia, and as his lineage expanded, so did the empire, ultimately stretching across three continents. Osman I's reign marked the beginning of a transformative period that would introduce significant cultural, political, and economic changes in the regions under Ottoman control.