Israeli historians Benny Morris and Dror Ze'evi have produced a work that shocks the conscience with their forensic study of the exterminatory violence committed during the final stage of the Ottoman Empire and the lead-up to the nascent phase of the Turkish Republic.

In contrast to scholarship that has largely focused on the World War I Ottoman extermination of Anatolia's Armenian population, The Thirty-Year Genocide: Turkey's Destruction of its Christian Minorities, 1894--1924 broadens that time frame to study other persecuted Christian minority groups, particularly Greeks and Assyrians.

Related: The Assyrian Genocide

An important lesson from this masterful history concerns the role that Islamic-animated genocide played in the destruction of the region's Christians. Morris and Ze'evi marshal no shortage of evidence.

Take the example of one sheik who, according to the British diplomat in Turkey Gerald Fitzmaurice, "ordered his followers to bring as many stalwart young Armenians as they could find. To the number of about 100 they were thrown on their backs and held down by their hands and feet, while the sheik, with a combination of fanaticism and cruelty proceeded, while reciting verses of the Koran, to cut their throats after the Mecca rite of sacrificing sheep." This massacre unfolded during a savage period of widespread targeting of Armenians that extended from 1894 to 1896.

The book abounds with examples of Islamic ideology being combined with state directives to promote the extermination of Middle Eastern Christians. It is not a historical study for the faint of heart.

The authors conclude that what happened was deliberate, state-engineered genocide aided by Muslim clerics and the Muslim-majority population. They base their conclusion on "the massive documentation -- American, British, French, German and Austro-Hungarian -- that we have studied over the past decade."

The Ottoman and Turkish Republic's policy of elimination reduced Asia Minor's Christian communities from 20% of the population at the end of the nineteenth century to 2% in 1924.

Morris and Ze'evi write, "The Turks and their helpers murdered, straightforwardly or indirectly, through privation and disease, between 1.5 and 2.5 million Christians between 1894 and 1924."

The rise of the Young Turks and the Ottomans' entry into WWI revealed a kind of grotesque historical irony. According to a contemporary witness, Wilfred Post, a doctor and missionary who was born and reared in Turkey, "The proclamation of the holy war, which failed to unite all Islam against the Entente, nevertheless had the effect of arousing the old fanatic spirit of the Turks themselves and they prosecuted the holy war within their own Empire with a zeal exceeding that of their forefathers."

The German diplomat and archeologist Max von Oppenheim produced the 1914 "Memorandum on the fomenting of rebellions among the Muslim subjects of our enemies" that was sent to Sultan Mehmed V for approval. In short, Oppenheim and Kaiser Wilhelm II convinced the Ottomans to urge Muslims worldwide to revolt against their colonial masters based on jihadi ideology.

Oppenheim's jihad failed while the Ottoman's internal jihad against Christians succeeded at the cost of spectacular violence and suffering for Christian minorities.

The collapse of the Ottoman Empire and the rise of the Turkish nationalist leader Mustafa Kemal (later Kemal Ataturk) did nothing to diminish the role of "jihadi rhetoric" as an organizing tool.

Kemal, the military hero associated with the Gallipoli campaign and who later become Turkey's president, declared there was a "national holy war now commencing to save our sacred race and fatherland from the danger of dismemberment."

Kemal made that statement after resigning from the army, saying he had then become a "crusader [mudjahid] fighting for the glory of the race."

This type of rhetoric and ideology would not bode well for Turkey's struggling Christian communities between 1918 and 1924.

Benjamin Weinthal is a fellow of the Foundation for Defense of Democracies.