The Ottoman Empire had entered the First World War on the side of the Central Powers in November 1914. Its eastern military campaign against Russia in the Caucasus had collapsed at the January 1915 Battle of Sarıkamış — approximately 60,000 of the Ottoman Third Army’s 90,000 troops had died of cold, hunger, and battlefield wounds in two weeks of winter campaigning.
The Ottoman political leadership — particularly the Committee of Union and Progress (CUP) cabinet, dominated by Talaat Pasha (Interior Minister), Enver Pasha (War Minister), and Djemal Pasha (Navy Minister) — chose to blame the military disaster on the Armenian Christian minority. The Armenians were accused — without documentary basis — of collaboration with the advancing Russian army.
The Armenian population of eastern Anatolia in 1914 was approximately 1.5 to 2.5 million people, predominantly farming and small-town communities that had been present in the region for two millennia. The CUP government decided across spring 1915 to deport the entire population east into the Syrian desert.
24 April 1915
The deportations began with a coordinated arrest operation on the night of 23-24 April 1915. Approximately 250 Armenian community leaders, intellectuals, clergy, and political figures in Constantinople were arrested in their homes by Ottoman police. Most were executed within weeks at the concentration centres at Çankırı and Ayaş. The 24 April 1915 date is now commemorated as Armenian Genocide Remembrance Day by Armenian communities worldwide.
The provincial deportations began the same month. Armenian villagers across six eastern Anatolian provinces — Erzurum, Bitlis, Van, Diyarbakır, Sivas, and Mamuret-ul-Aziz — were ordered to abandon their homes within 24-48 hours and assemble for deportation marches eastward. The men of military age (approximately 20-45) were typically separated from the columns within the first day and shot.
The deportation marches ran through summer and autumn 1915. The destination was the Syrian desert south of the Euphrates river, approximately 500-800 km from the deportees’ origin points. The marches were conducted on foot through the Anatolian highlands in summer heat without food, water, or medical care.
The methods
The direct killing methods documented across the 1915-1916 period included:
— Mass execution by gunfire at isolated points along the deportation routes — Drowning in the Euphrates, Tigris, and Kemah Gorge rivers — bodies were systematically thrown over cliff edges — Mass burning in barns and caves with accelerants — Death marches without food, water, or medical care — Starvation and disease in the concentration camps along the lower Euphrates at Der Zor
The concentration camp system along the Euphrates ran from approximately Meskene through Raqqa to Der Zor. Approximately 500,000 Armenians arrived at Der Zor between August 1915 and spring 1916. Approximately 200,000 of them died in the camp itself; approximately 200,000 more died in coordinated massacres in the surrounding desert between May and August 1916 — the Der Zor massacres.
The cumulative death toll across the 1915-1916 period is conventionally estimated at approximately one million — about half to two-thirds of the 1914 Anatolian Armenian population. The figure does not include the Armenian Christian communities of the Russian Caucasus or the Armenian-speaking diaspora.
The American ambassador
The American ambassador to the Ottoman Empire Henry Morgenthau Sr documented the deportations and killings in real time from his Constantinople embassy. His 1918 memoir Ambassador Morgenthau’s Story is the principal English-language contemporary record.
Morgenthau’s reported conversation with Talaat Pasha in late summer 1915 captures the Ottoman political position. Talaat had asked Morgenthau for lists of American life-insurance policies held by Armenians, on the grounds that the policy-holders were all now dead and the Ottoman government was the rightful beneficiary. Morgenthau refused. The Talaat letter survives in the Morgenthau papers at the Library of Congress.
What followed
The Ottoman Empire lost the First World War. The CUP leadership fled to Germany in November 1918. The postwar Ottoman courts-martial of 1919-1920 — convened under Allied military occupation pressure — convicted Talaat, Enver, and Djemal in absentia of mass killing and deportation crimes. The verdicts were set aside after the Turkish War of Independence (1919-1923) reversed the Allied occupation.
Talaat was assassinated in Berlin on 15 March 1921 by the Armenian survivor Soghomon Tehlirian in Operation Nemesis — a coordinated Armenian Revolutionary Federation programme of assassinations of the CUP leadership. Tehlirian was acquitted by the Berlin court on grounds of psychological trauma. Djemal was killed in Tbilisi on 25 July 1922 by Armenian assassins. Enver was killed by Bolshevik troops in Tajikistan on 4 August 1922 while leading a Basmachi anti-Soviet rising.
The Turkish Republic founded by Mustafa Kemal Atatürk in 1923 denied — and continues to deny in 2026 — that the 1915-1916 events constitute genocide. The Turkish official position is that the killings were wartime casualties of deportation under military necessity, that mutual killings occurred between Turks and Armenians, and that the death toll was smaller than 1 million.
The international recognition of the Armenian genocide as genocide has been progressive but incomplete. As of 2026 approximately 35 national governments — including France, Germany, Russia, Italy, Canada, and (since April 2021) the United States — formally recognise the 1915-1916 killings as genocide. The Republic of Turkey has recalled its ambassadors from recognising states in protest of each declaration.
The Der Zor desert site — the principal mass killing site of the genocide — holds a Armenian church and pilgrimage site that was built between 1989 and 1991. The church was destroyed by Islamic State forces in September 2014 during the Syrian Civil War. The ruins are still standing in 2026.