Ottoman Empire explained: how it rose, reached its golden age, and fell

The Ottoman Empire began as a small principality in northwestern Anatolia around 1299, founded by Osman I, and grew over six centuries into a state that at times stretched from the gates of Vienna to the Indian Ocean. It formally ended in the early 1920s. Below is what historical sources say about how it rose, how it reached its peak under Suleiman the Magnificent, and why it eventually collapsed, according to History.com, National Geographic, The Lausanne Project and the Topkapi Palace historical account.

How the Ottoman state began

According to History.com, Osman I established the Ottoman Empire around 1299 in Anatolia, and the name "Ottoman" comes from his Arabic name, Uthman. His successors Orhan, Murad I and Bayezid I expanded Ottoman territory in the following decades. Ottoman forces first crossed into Europe in the mid-14th century, advancing through Thrace and the Balkans and cutting Constantinople off from its Balkan hinterland.

The turning point came in 1453, when Sultan Mehmed II, known as Mehmed the Conqueror, captured Constantinople after a siege, ending the roughly 1,000-year-old Byzantine Empire, according to History.com. Mehmed renamed the city Istanbul and made it the Ottoman capital, which History.com describes as becoming a major centre of trade and culture under Ottoman rule.

National Geographic notes that Ottoman governance was structured so that the position of sultan was the only hereditary role in the state; other elite positions in the bureaucracy and military were filled on the basis of merit and service rather than birth. This system, combined with control over major trade routes, helped generate the wealth and administrative strength that fueled further expansion.

The golden age under Suleiman the Magnificent

The empire reached what historians describe as its peak under Suleiman I, who reigned from 1520 to 1566 and is known in Turkish as "Kanuni" (the Lawgiver). According to the Topkapi Palace historical account, his 46-year reign brought territorial expansion, legal reform and cultural growth, with his authority reaching, in the source's description, "from the gates of Vienna to the shores of the Indian Ocean." He personally led thirteen major military campaigns, including the conquest of Belgrade and Rhodes and victory over Hungary at the Battle of Mohács, while his admiral Barbarossa Hayreddin Pasha extended Ottoman naval power across the Mediterranean.

Suleiman also commissioned a comprehensive reorganisation of Ottoman law, producing the Kanun-i Osmani, which the Topkapi Palace account says harmonised sultanic law (kanun) with Islamic religious law (sharia) into a single coherent legal system that endured for centuries. Under his patronage, the chief architect Mimar Sinan designed landmark structures including the Süleymaniye Mosque in Istanbul, while the palace's imperial workshops produced calligraphy, miniature painting and ceramics that set aesthetic standards across the empire, according to the same source.

National Geographic adds that under Suleiman the arts, technology and architecture advanced significantly, describing the period as the empire's cultural and political high point across Eastern Europe, North Africa and the Middle East.

Decline: from Vienna to the "sick man of Europe"

Ottoman power began to weaken after a failed attempt to capture Vienna in 1683, according to both History.com and National Geographic. Subsequent military losses led the empire to cede Hungary by 1699, and further wars with Russia, Austria and Poland eroded Ottoman territory through the 18th century.

National Geographic attributes the longer decline to a mix of factors: internal political intrigue, the strengthening of European states, competition from new trade routes opened by European exploration, and later industrialisation that outpaced Ottoman economic development. History.com lists specific territorial losses, including Greek independence in 1830 and the loss of most remaining European territory in the Balkan Wars of 1912–1913. By the 19th century, National Geographic says the empire had earned the label "sick man of Europe," reflecting its shrinking territory, economic troubles and growing dependence on European powers.

World War I and the empire's end

The Ottoman Empire's alliance with Germany in World War I proved decisive for its collapse. National Geographic reports that over two-thirds of Ottoman military forces became casualties during the war, and that up to 3 million civilians died, including an estimated 1.5 million Armenians. The empire's defeat in the war led to the imposition of the Treaty of Sèvres in 1920, which Turkish Nationalists rejected.

The Lausanne Project, an academic initiative on the treaty's history, states that the Nationalist regime led by Mustafa Kemal had by then already dethroned the sultan, and that the Treaty of Lausanne, signed on 24 July 1923, replaced Sèvres and granted formal international recognition to the new Turkish state. According to the same source, Turkey was proclaimed a Republic in October 1923, and the Ottoman caliphate — the last remaining institution of the old monarchy — was abolished in March 1924. History.com similarly states that the sultan's title was eliminated in 1922 and that Turkey became a republic on 29 October 1923 under Mustafa Kemal Atatürk.

Why this history still matters

The Ottoman Empire's roughly six-century span shaped the borders, legal traditions and cultural landscape of modern Southeast Europe, the Middle East and North Africa. Its governance model — a hereditary sultan atop a merit-based bureaucracy, as described by National Geographic — and its legal synthesis under Suleiman are frequently cited by historians as reasons the state endured as long as it did before 20th-century wars and nationalism brought it to an end.