The 1876–77 Constantinople Conference of the Great Powers (Austria-Hungary, Britain, France, Germany, Italy and Russia) was held in Constantinople from 23 December 1876 until 20 January 1877. Following the beginning of the Herzegovinian Uprising in 1875 and the April Uprising in April 1876, the Great Powers agreed on a project for political reforms in Bosnia and in the Ottoman territories with a majority-Bulgarian population. The Ottoman Empire refused the proposed reforms, leading to the Russo-Turkish War a few months later.
In the subsequent conference's plenary sessions, the Ottoman Empire submitted objections and alternative reform proposals that were rejected by the Great Powers, and attempts to bridge the gap did not succeed. Eventually, on 18 January 1877 Grand Vizier Midhat Pasha announced the definitive refusal of the Ottoman Empire to accept the conference decisions. The rejection by the Ottoman Government of the decisions of the Constantinople Conference triggered the 1877–1878 Russo-Turkish War, depriving at the same time the Ottoman Empire – in contrast to the preceding 1853–1856 Crimean War – of Western support.