Maurice, who meanwhile succeeded Tiberius, intervened in a Persian civil war, placed the legitimate Khosrau II back on the throne, and married his daughter to him. Maurice's treaty with his new brother-in-law enlarged the territories of the Empire to the East and allowed the energetic Emperor to focus on the Balkans. By 602, a series of successful Byzantine campaigns had pushed the Avars and Slavs back across the Danube. However, Maurice's refusal to ransom several thousand captives taken by the Avars, and his order to the troops to winter in the Danube, caused his popularity to plummet. A revolt broke out under an officer named Phocas, who marched the troops back to Constantinople; Maurice and his family were murdered while trying to escape.