Murad I was the Sultan of the Ottoman Empire from 1362 to 1389. He is known for expanding the empire significantly, particularly in the Balkans. Under his leadership, the Ottomans captured important territories, including Thessaloniki and Adrianople, which became a key city for the empire. Murad I also established a more organized military structure, introducing the elite Janissary corps. His reign marked a turning point for the Ottomans, as they transitioned from a small principality to a powerful empire. Murad I's legacy continued to influence the empire long after his death in battle against the Serbs at the Battle of Kosovo.