This war was a conflict which broke out when Bulgaria, dissatisfied with its share of the spoils of the First Balkan War, attacked its former allies, Serbia and Greece. Serbian and Greek armies repulsed the Bulgarian offensive and counter-attacked, penetrating into Bulgaria. Having previously engaged in territorial disputes with Romania, the new war caused a Romanian intervention against Bulgaria. The Ottoman Empire also took advantage of the situation to regain some lost territories from the previous war. When Romanian troops approached the capital Sofia, Bulgaria asked for an armistice, resulting in the Treaty of Bucharest, in which Bulgaria had to give up much of its First Balkan War gains to Serbia, Greece, Romania and the Ottomans.