Fables and legends that feature the origins of the Ottoman Empire indicate that Osman, a Turkish tribesman, was the original ruler responsible for founding the civilization that nearly brought Christian Europe to its knees. Narratives indicate that Osman's tribe, the Kayi, fled west from the Mongols in the 13th century and took control of a freebooting army of nomads and Muslim peasants who inhabited the rugged stretch of wasteland along the Byzantine frontier. This band of refugees enjoyed close ties to Muslim guilds and religious brotherhoods in local towns that were led by Sheikh Edebali, who allowed Osman to form a tiny state around his castle of Karacahisar. Turkish warriors and religious leaders who also fled from the pagan Mongols in the east quickly populated this region, ruled by Osman. Osman directed his community through the Kara Su valley to seize Yenisehir, and establish it as the first true Ottoman capital. The Ottoman state emerged, poised above the fertile shores of the Sea of Marmara.

Osman continued to wage a slow but persistent war against the Byzantine Empire who endeavored to defend their territories along the Asiatic shores that were opposite of Constantinople (now Istanbul). His first victory over a Byzantine army at Koyunhisar in 1301 AD perpetuated Osman's fame, and settlers flocked to Ottoman territory as a result. Osman extended his control over several other Byzantine fortresses, providing the Ottomans with strong bases from which they could lay siege to Bursa and Nicaea in northwest Anatolia. The pinnacle of Osman's reign occurred at the conquest of Bursa shortly before his death.

Initially, Ottoman war tactics were no different than those used by the tribal Turks. They would first harass the foe with horse-archers, employing hit and run tactics, only closing in on the enemy when they became completely disorganized. Thus, the earliest Ottoman successes were won against isolated Byzantine garrisons, but rarely against a field army. In order to capture fortified towns the Ottomans ravaged the countryside and imposed blockades. Afterwards, the Ottomans would revive the town's trade and increase its population so that it could then be consolidated into the Empire as a productive and functioning city. During their earliest exploits, the Ottomans were frequently frustrated by fortifications and the exhausting sieges that were required in order to overcome these defenders. This changed in the 15th century and beyond as imported expertise in firearms and gunpowder led to some of the most massive artillery of the time. A form of Turkish heavy cavalry, known as Sipahi, became the predominating military unit utilized by the Ottoman Empire. The earliest variations of these soldiers were well-armored men on well-armored horses, who typically used a mace as their primary weapon. During the 17th century the Sipahi replaced their archaic weaponry with sabers and pistols, establishing them as a fearsome presence on the battlefield. While European infantry were more than a match for the standard Ottoman infantry, the Sipahi were far superior to any medieval knights.

During their period of expansion, the Ottomans visualized Europe, as Americans would later see their Western frontier, a land of destiny. The conquest of Istanbul in 1453 AD initiated this by uniting Muslim Anatolia andChristian Rumelia under the Ottoman Sultan's protection. However this attitude would change as the Ottomans were forced to go on the defensive during the 17th and 18th centuries. Ottoman defeats were followed by mass slaughters of Muslim minorities. These massacres characterized the war between Christian and Turk in the 19th century.

At its height, the Ottoman Empire included territory such as: Hungary, Serbia, Bosnia, Romania, Greece, the Ukraine, Iraq, Syria, Israel, Egypt, a large section of North Africa, and most of the Arabian Peninsula. Over time however, Sultans grew weary of their administrative duties and withdrew from public affairs. The office of Grand Vizier was created to act second only to the sultan in authority and revenue, but while the Grand Vizier was able to stand in for the sultan in an official capacity, he could not take his place as a focus of loyalty among the different classes and social groups in the empire. This separation of political loyalty and centralized authority led to a decline in the government's ability to impose its will, which inevitably led to the Ottoman Empire's end in 1922, when it was replaced by the Turkish Republic.

In Civilization III: Play the World, the Ottomans are considered a Scientific and Industrious civilization, therefore, they start with Bronze Working and Masonry and have significant bonuses to building and scientific activities. See the developer update on Civ-specific abilities for more on these bonuses.

Unique Unit: The Sipahi

During the 15th century and beyond the Ottomans imported expertise in firearms and gunpowder. A form of Turkish heavy cavalry, known as Sipahi, became the predominating military unit utilized by the Ottoman Empire. The earliest variations of these soldiers were well-armored men on well-armored horses, who typically used a mace as their primary weapon. During the 17th century the Sipahi replaced their archaic weaponry with sabers and pistols, establishing them as a fearsome presence on the battlefield. While European infantry were more than a match for the standard Ottoman infantry, the Sipahi were far superior to any medieval knights.

An Ottoman city must have horses and saltpeter to build a Sipahi. They replace Cavalry and are very strong offensive units.