Osman I, also called Osman Gazi, the founder of the Ottoman Empire, transformed the Kayı tribe into a powerful political force in western Anatolia, laying the foundations of an empire that would eventually span three continents through military success, strategic leadership and a governance model centered on justice, according to a Turkish historian.
Known for his courage, military skill and political foresight, Osman Gazi expanded his territory through a series of conquests while establishing the administrative framework of the emerging Ottoman Empire. Historians say his leadership was shaped by the governance traditions inherited from his father, Ertuğrul Gazi, as well as the spiritual guidance of Sheikh Edebali.
By defeating neighboring Byzantine fortress lords, known as tekfurs, and implementing policies aimed at protecting local communities, Osman Gazi earned the trust of the population and secured stability in newly conquered territories, paving the way for the Ottoman Empire's rapid expansion.
Following the conquest of Bursa in 1326, Osman Gazi was buried in the city's Tophane district in accordance with his final wish. His tomb remains one of the most significant symbols of respect for the founder of the Ottoman Empire and continues to attract visitors.
Since September 2020, an honor guard organized by the Bursa Provincial Gendarmerie Command has maintained a continuous vigil at the mausoleum as part of commemorations marking the 98th anniversary of Bursa's liberation from enemy occupation.
Yusuf Ziya Karaaslan, an assistant professor in the Department of History at Bursa Uludağ University, said Osman Gazi was the son of the leader of a Turkmen tribe that migrated from the Iranian region to Anatolia.
He described Osman Gazi as an "alp gazi" – a title referring to both a warrior and a champion of the Islamic frontier – emphasizing his identity as a military leader.
"He was a bold and courageous leader," Karaaslan said. "After the conquest of Karacahisar, we see him emerging as a prominent figure. Together with commanders such as Konur Alp, Turgut Alp and Hasan Alp, he fought against Byzantine forces and the tekfurs across much of southern Marmara, demonstrating both military leadership and statesmanship."
Karaaslan said Osman Gazi played a decisive role in transforming the Ottoman principality from a frontier beylik into a regional power.
After the conquests of Karacahisar, Eskişehir, Yenişehir and Bilecik, Osman Gazi advanced toward Bursa, a campaign that marked a turning point for the fledgling state.
"Following the conquest of Bursa in 1326 and Iznik in 1331, the Ottoman principality began to emerge as a regional power," Karaaslan said. "His policies of conquest, gaza and istimalet – winning the support of local populations through fair treatment – enabled the Ottomans to establish a tradition that would later expand into Rumelia and eventually develop into an empire ruling three continents."
He added that Osman Gazi also ensured continuity by raising his son, Orhan Gazi, alongside experienced frontier warriors, allowing him to strengthen the state's military organization and carry Ottoman institutions into the next generation.
Karaaslan also highlighted Osman Gazi's final wish during the siege of Bursa.
"During the siege, while looking at the city from the eastern side, he is recorded as saying, 'When I die, bury me in that silver-domed tomb,'" Karaaslan said. "The site where his mausoleum stands today was known during the Byzantine period as the Monastery of Saint Elias. Its dome was clearly visible from afar, making it a symbolic landmark overlooking Bursa."
Marking the 700th anniversary of Osman Gazi's death, Karaaslan summarized the founder's legacy through five defining characteristics: a Gazi for his commitment to the Islamic frontier tradition, an Alp for his roots in the Turkic warrior culture of Central Asia, a Just Ruler for his policies, a Leader for guiding his companions through collective decision-making, and a Conqueror for his military achievements.
"It is important to remember Osman Gazi as a ruler who lived among his people," Karaaslan said. "Historical sources indicate that after the conquest of Karacahisar, he personally inspected the marketplace established there. An ordinary person living during his reign could easily have encountered him. At the same time, he was a commander who led his warriors on the front lines, directing sieges and shaping military strategy."
