On this day, June 4, 1878, the Treaty of Constantinople was signed, transferring the administration of Cyprus from the Ottoman Empire to the British Empire

• On June 4, 1878, the Treaty of Constantinople (Anglo-Turkish Convention) is signed, under which Cyprus passes from the Ottoman Empire to British Empire It was negotiated in strict secrecy in Constantinople during the Berlin Congress (1878).

The Treaty of Constantinople (1878) was a secret bilateral treaty concluded between the British Empire and the Ottoman Empire on June 4, 1878. It was concluded, in the utmost secrecyin Constantinople during the time of the Congress of Berlin (1878), which resulted in the well-known Treaty of Berlin (1878). In essence, this treaty was directed against Russiaeven though just five days earlier the Anglo-Russian Agreement of London (1878) had been concluded in London, thereby averting a looming Anglo-Russian war. The dates in the text are according to the new calendar. The treaty was signed on May 22 according to the old calendar.

Under this treaty, which consisted of only two articles in addition to the preamble, the British Empire undertook to assist Sultan Abdul Hamid II with military force in defending the regions of Batum, Ardahan, and Kars in the event that Russia sought to seize these regions or attempted to occupy other Ottoman territories in Asia (Article 1).

In exchange, the Sultan promised the British Empire that he would carry out the necessary internal administrative reforms and provide protection for Christians and other subjects of different faiths (Article 1).

Additionally, the Sultan agreed to the cession of Cyprus to the British Empire with full rights to its occupation and administration. A time limit for entry into force (ratification) was set at no later than one month from the date of conclusion (Article 2).