In 1444 the major princes of the Albanian Principalities, which up to that point had been vassals of the Ottoman Empire, united and formed the League of Lezhë, an anti-Ottoman confederacy under Skanderbeg's lead. As a result, the Ottoman Empire sought to crush the League and re-establish control over Albania. As of 1448, all Ottoman expeditions into Albania had failed and Murad II chose lead a force in person into Albanian territory and fragment the League.