On August 10, 1913, the Bucharest Peace Treaty was concluded between Romania, Serbia, Montenegro and Greece, on the one hand, and Bulgaria, on the other. The document put an end to the Second Balkan War.
Under pressure from the Romanian troops, which had reached the vicinity of Sofia, Bulgaria was forced to cede Southern Dobrudja to Romania and to abandon its claims to Macedonia. According to the treaty, Serbia received the Vardar, and Greece - the Aegean share of the region. Bulgaria retained the Pirin region and Western Thrace. She refused to accept these terms as final and during World War I joined the Central Powers to seek revenge against Serbia.
After the signing of the London Peace Treaty on May 17, 1913, relations within the victorious coalition became strained.
The treaty ended the war, but did not eliminate the military situation in the Balkans. The reason was the tension that arose between the main players in the winning coalition.
If a year ago Bulgaria managed to create an effective and successful bloc against the Ottoman Empire through diplomacy, then in the months surrounding the preparation of the peace treaty in London Sofia fell into international isolation.
According to some historians, blinded by military successes, Tsar Ferdinand ordered our army to attack the recent allies Greece and Serbia on June 16, 1913.
He was impatient to wait for the arbitration of the Russian Tsar. The consequences were deplorable for Bulgaria. On June 27, 1913, Romania declared war on Bulgaria and reached Vratsa with almost no resistance. At Belogradchik, it met the Serbian army. Vidin fell into encirclement. The reason is that the main Bulgarian forces are thrown against the Greeks and Serbs.
On July 5, the government of Vasil Radoslavov announced that it agreed to cede Southern Dobrudja to Romania and asked for an armistice. In response, Romanian Prime Minister Titu Maiorescu invited the warring parties to peace talks in Bucharest. Bulgaria responded first and sent its representatives to the Romanian capital on July 13. Three days later, delegations of the former Bulgarian allies - Greece, Serbia and Montenegro - also arrived in Bucharest.
The Bucharest Conference began on July 17. At this time, military actions continued, because Serbia and Greece insisted on negotiating peace terms before the fire was stopped. However, the successful resistance of the Bulgarians near the Kresna Gorge persuaded Greece to an armistice (July 18). On July 21, an agreement was reached on the new border between Bulgaria and Romania, but the efforts of Bulgarian diplomats to gain Romanian support against the Serbs and Greeks remained unsuccessful.
The Bulgarian-Serbian and Bulgarian-Greek border issues were settled by July 24. Initially, Pašić proposed the Struma River as the border. This proposal was not accepted, but the Bulgarians were forced to give up Štip, Radovish and Kočani, which they had held until the war. Venizelos demanded the entire Aegean coast up to the village of Makri (a few kilometers west of Dedeagach), but under pressure from the other participants in the conference, he reduced his claims. Russia and Austria-Hungary intervened in favor of Bulgaria in the negotiations for Kavala, but Venizelos managed to gain support from two other great European powers - France and Germany. Ultimately, the Bulgarian delegates surrendered Kavala under Mayorescu's threat that Romanian troops would occupy Sofia.