Following the collapse of the Ottoman Empire, the Greco-Turkish War (1919-1922), and the establishment of the Republic of Turkey, the population exchange agreement signed between Greece and Turkey resulted in the uprooting of all Greeks in modern Turkey (and Turks in Greece) from where many of them had lived for centuries. But due to the Greeks' strong emotional attachment to their first capital as well as the importance of the Ecumenical Patriarchate for Greek and worldwide Orthodoxy, the Greek population of Istanbul was specifically exempted and allowed to stay in place. Nevertheless, this population began to decline, as evinced by demographic statistics.