 During the First World War, Rûm, alongside Ottoman Greeks, were targeted by the Ittihadist Ottoman authorities in what is now historically known as the Ottoman Greek genocide.As a result, three Antiochian Greek Orthodox Dioceses were completely annihilated; the Metropolis of Tarsus and Adana, the Metropolis of Amida, and the Metropolis of Theodosioupolis.Those Antiochians living outside of the French Mandate for Syria and the Lebanon were subject to the forced population exchange of 1923, which ended the Ottoman Greek Genocide.