Treaty of Constantinople (1913)
In the First Balkan War, the coalition of Bulgaria, Serbia, Greece and Montenegro defeated the Ottoman Empire. The Ottomans lost nearly all their European possessions, save for a small territory around the Sea of Marmara by the Treaty of London. The Ottomans however were able to recover Eastern Thrace during the Second Balkan War. Although peace talks between Bulgaria and her other neighbours were held in Bucharest, the Ottoman Empire was not represented there and conducted separate negotiations which led to the Treaty of Constantinople.
- Bulgaria acknowledged Ottoman gains of Edirne, Kırklareli and Didymoteicho and the surrounding territory
- The Ottoman Empire ceded the port of Dedeagach (mod. Alexandroupoli) to Bulgaria
- The exchange of lands was to be completed within 10 days
- The armies on the border would be demobilized within three weeks
- Prisoners of war from both sides would be released
- Both political and economical ties between the two countries would be reestablished
The Ottoman Empire and Bulgaria were allies in the Central Powers in the First World War. During the war, the Ottoman government decided to cede Didymoteicho to Bulgaria (probably to persuade Bulgaria to join the war). However the Central Powers were defeated in 1918 and Bulgaria lost both Western Thrace and Didymoteicho to Greece.
The treaty largely defines the modern-day borders between Eastern Thrace, Bulgaria and Greece. Under the terms of the abortive Treaty of Sèvres, Turkey was to cede almost all of Eastern Thrace to Greece, but the proposed territorial changes were negated by Turkey's victory over Greece in the War of Independence and the subsequent Treaty of Lausanne, which reaffirmed the borders established by the Constantinople agreement.