What Caused the Rise — and Fall — of the Ottoman Empire?

Osman Gazi is known as the father of the Ottoman dynasty, the first in a long line of military leaders and sultans who came to rule the Ottoman Empire for six centuries. In fact, the word Ottoman in English derives from the Italian pronunciation of Osman's name.

Osman was born in 1258 in the Anatolian town of Söğüt (in modern-day Turkey). He led one of many small Islamic principalities in the region at the time, but Osman wasn't satisfied with a provincial kingdom. He raised an army of fierce frontier warriors known as Ghazis and marched against Byzantine strongholds in Asia Minor.

According to Ottoman lore, Osman had a dream in which all the known world was unified under Ottoman rule, symbolized by the canopy of a massive tree rising from his body and covering the world. This vision, first published 150 years after Osman's death, provided divine authority for the Ottoman conquests to come, explained historian Caroline Finkel in "Osman's Dream: The History of the Ottoman Empire."

In 1453, Sultan Mehmed II, aka Mehmed the Conqueror, laid siege to the greatly weakened Byzantine capital of Constantinople. Although its population had dwindled, the fabled city still had its impenetrable walls. But the Ottomans came prepared with a new type of weaponry: cannons.

"The Ottomans were some of the first to employ artillery on a mass scale in the 15th century," says Chris Gratien, a history professor at the University of Virginia and co-creator of the Ottoman History Podcast. Mehmed bombarded the fortified city walls for weeks before his army broke through, making Constantinople (later Istanbul) the new Ottoman capital, which it would remain for over four centuries.

By unseating the Byzantine Empire, Sultan Mehmed could claim his place in the Roman imperial tradition. It's at this moment, historians believe, that the Ottoman Empire was born.

The Ottomans and most of their functionaries were Muslim, but the sultans and the ruling elite were strategic and pragmatic about the role of religion in their ever-expanding empire.

For conquests of predominantly Muslim regions like Egypt, the Ottomans established themselves as the true caliphate without completely erasing their Muslim subjects' existing political structure. Non-Muslim communities throughout the Mediterranean governed much of their own affairs under the Ottomans, as Christians and Jews were considered "protected people" in the Islamic political tradition.

Gratien says that the Ottomans were able to successfully govern and maintain such an extensive land empire not only through military might but "a combination of cooption and compromise."

In the 16th century, the Ottoman Empire reached its territorial and political apex under the 46-year rule of Suleiman I, better known as Suleiman the Magnificent, who was intent on making his Mediterranean kingdom a European superpower.

Militarily, this was the "period of peak Ottoman dominance," says Gratien. Suleiman commanded an elite professional fighting force known as the Janissaries. The fighters were taken by force from Christian families as youth, educated and trained as soldiers and made to convert to Islam. Fearless in battle, the Janissaries were also accompanied by some of the world's first military bands.

Suleiman's reign also coincided with a period of great wealth for the Ottoman Empire, which controlled some of the most productive agricultural land (Egypt) and most trafficked trade routes in Europe and the Mediterranean.

But Gratien says that the Age of Suleiman was about more than just power and money; it was also about justice. In Turkish, Suleiman's nickname was Kanuni — "the lawgiver" — and he sought to project the image of a just ruler in the Islamic tradition. In larger towns across the empire, citizens could take their disputes to local Islamic courts, the records of which are still around today. Not just Muslims, but Christians and Jews. And not just men, but women.

"These were places where women could go claim their rights in cases of inheritance or divorce, for example," says Gratien.

A fascinating and somewhat overlooked figure in Ottoman history is Roxelana, the wife of Suleiman the Magnificent. As historian Leslie Peirce showed in his book "Empress of the East: How a European Slave Girl Became Queen of the Ottoman Empire," Roxelana, known as Hürrem Sultan in Turkish, ushered in a new age of female political power in the palace, sometimes known as the "Sultanate of Women."

Roxelana was a non-Muslim kidnapped by slavers at 13 and eventually sold into the sultan's harem. According to Ottoman royal tradition, the sultan would stop sleeping with a concubine once she bore him a male heir. But Suleiman stuck with Roxelana, who bore him a total of six children and became one of his closest confidantes and political aides — and perhaps most shockingly, his wife.

Thanks to Roxelana's example, the imperial harem took on a new role as an influential political body, and generations of Ottoman women ruled alongside their sultan husbands and sons.

In 1683, the Ottomans tried for a second time to conquer Vienna but were repulsed by an unlikely alliance of the Hapsburg Dynasty, the Holy Roman Empire and the Polish-Lithuanian Commonwealth. Not only did the Ottomans fail to capture Vienna, but they ended up losing Hungary and other territory in the ensuing war.

The once unbeatable Ottoman fighters suffered loss after loss throughout the 18th and 19th centuries as more Ottoman territories declared independence or were snatched up by neighboring powers like Russia.

But Gratien says that while the Ottoman Empire shrunk in size, it also centralized its government and become more involved in the lives of its citizens. It raised more taxes and opened public schools and hospitals. The economy and population density grew rapidly in the 19th century even as the military suffered painful losses. The Ottoman Empire also became the destination for millions of Muslim immigrants and refugees from former Ottoman lands and neighboring regions.

"Large-scale immigration is associated with places like the United States in the 19th century, but people don't think of the Ottoman Empire as something that was also growing and dynamic during that time," says Gratien.

In the late 19th century, the Ottoman Empire experimented with a constitutional monarchy and an elected parliament, but that came to end in 1878 when Sultan Abdülhamid II dissolved the democratic institutions and ushered in 30 years of autocratic rule.

Abdülhamid's hardline approach sowed the seeds of revolution, and the leading Ottoman opposition group was the Committee of Union and Progress party (CUP), also known as the "Young Turks." Though its leaders were Turkish nationalists, the CUP formed a coalition of ethnoreligious groups, including Armenians, Jews, Arabs, Greeks and Albanians.

The Young Turks wanted to restore the constitution, limit the monarchy and reestablish the greatness of the empire. Their victory in the 1908 revolution was widely celebrated as a win for liberty, equality, and Ottoman brotherhood. But the revolution quickly soured as factions split and more ardent nationalists consolidated what became increasingly authoritarian rule.

Coinciding with this internal turmoil was the First Balkan War in 1912, in which the Ottomans lost their remaining European territory in Albania and Macedonia. And as World War I approached, the militarily weakened Ottomans threw their fate in with Germany, who they hoped would protect them from their bitter enemy Russia.

With the ultranationalist wing of the Young Turks in charge, the Ottoman government initiated a plan to deport and resettle millions of ethnic Greeks and Armenians, groups whose loyalty to the crumbling empire was in question.

Under the cover of "security concerns," the Ottoman government ordered the arrest of notable Armenian politicians and intellectuals on April 24, 1915, a day known as Red Sunday. What followed was the forced deportation of more than a million Armenian citizens, including death marches across the desert to Syria and alleged massacres by soldiers, irregulars, and other armed groups in the region. In all, an estimated 1.5 million Armenians (out of 2 million in the Ottoman Empire) were killed between 1915 and 1923, according to the Armenian Genocide Museum-Institute.

Most scholars and historians agree that what happened to the Ottoman Armenians constitutes ethnic cleansing and genocide, but Turkey and a number of its allies still refuse to call it by that name.

Defeat in World War I was the final death blow to the Ottoman Empire, but the sultanate wasn't officially dissolved until 1922, when the Turkish nationalist resistance leader Mustafa Kemal Atatürk rose to power and established a secular republic. Under his decades-long, one-party rule, Atatürk tried to erase Ottoman institutions and cultural symbols, brought in Western legal codes and laid the foundation for modern Turkey.