奥斯曼一世（1258年—1326年），外文名Osman I，土耳其奥斯曼王朝开国苏丹，生于土耳其北部城市瑟于特，为部落首领的儿子，年轻时统领部落镇守罗姆王朝边境，后来趁罗姆王朝衰落而起兵自立，1299年登基称苏丹，以自己的名字奥斯曼作为国号，在位期间励精图治，奠定奥斯曼王朝日后成为横跨亚欧非三大洲的强大帝国的基础，1326年因病驾崩，终年68岁，在位27年。

In his early years, Osman practiced martial arts with his father and helped his father guard the border for the Sultanate of Roma. He studied Sufi theory at the local Sufi sect elder Edbali's appointment office, and married his daughter, Mal Hatton.
In 1281, he succeeded his father as a tribal leader and attacked the Bayi position on the border. He allied with the leader of the Sufi Mission and the Ghazi Society (the organization of the free people) to gradually improve his political prestige. He recruited the army, strengthened the military strength, and continued to expand outwards. He led the army to defeat the mercenaries of the Byzantine Empire for many times. He successively occupied the strongholds of Karajahisar, Bilegjik, and Yarshisar, and set his capital at Yenisehir.
In 1289, the Roma Sultan was forced to recognize all the territories he had seized as his fiefs. At the end of the 13th century, the royal family of the Roma Sultan declined, and the Bayi of the small Turkish principalities in the territory became independent one after another.
In 1299, Ottomans took this opportunity to officially declare independence, called "Ghazi", and established the Ottoman dynasty, becoming one of the powerful principalities in Asia. When he was in power, he declared the Sunni religious doctrine as the orthodox belief, followed the Hanifi school's religious law, and domestic religious issues were decided by religious jurists through consultation. Osman himself believed in piety, strictly abided by religious practice, lived frugally, and had a strong jihad spirit. He once paid tribute to the Ilkhanate of Persia on behalf of the principalities of Türkiye Minor Asia. According to historical records, after the death of Osman, his family had only dozens of weapons, more than 10 horses and more than 200 sheep. Türkiye's historical records call it "tribal leader, Ghazi hero".
Osman may be the most famous emperor in history. His name has been the name of the Ottoman Empire for more than 600 years. This huge empire spans Asia, Africa and Europe, strangles the throat of mainland traffic, and has long been one of the most powerful and prosperous empires in the world.
Turks, a nation that has experienced many vicissitudes in the great migration of nations in the world, have left their footprints from the western Iranian plateau to Asia Minor. In Asia Minor, they became the people of Allah. Later, under the pressure of the Mongols, about 400 families of them lived in Ertu, the leader ğ Rul) moved to Asia Minor and found a place to settle down in this beautiful land. At that time, most of Asia Minor was controlled by the Roma Sultanate of Turks. The Roma Sultanate gave generous treatment to fellow Ottomans and granted the Suogud region in northwest Asia Minor bordering the Byzantine Empire to Ertugrur as a vassal to defend the Roma Sultanate. Eltu Gruller was Ottoman's father.
In 1290, Eltu Grulle died, and 32 year old Osman inherited the position of leader. At that time, great changes had taken place in the international situation. While the Ottoman country was thriving, its suzerain, the Sultanate of Roma, fell apart under the repeated attacks of the Mongols, and finally came to its end in 1308. At the critical moment, Osman took over the banner of Türkiye and declared independence in 1299, calling himself Emir.
In 1300, he called himself Sudan (meaning the most authoritative person), which was the source of the Ottoman Türkiye Empire for more than 600 years.

Ottoman was an outstanding strategist and organizer. Under his leadership, the Ottoman country continued to grow. In addition to his outstanding talents, the reasons for his success are as follows:
1. He held high the banner of holy war, and in the name of God, he gathered religious and semi religious groups under his own banner to gather a powerful force;
2. He generously granted land to those who made contributions in the holy war, thus winning the hearts and minds of people;
3. He has a broad mind. In addition to Turks, he has also accepted a large number of Muslim fighters from other ethnic groups, even non Muslims.
A lucky marriage boosts prestige
Osman was appreciated by Sheikh, the respected Sufi sect elder of Islam, for his talent and bearing, and married his daughter Malha. This lucky marriage greatly helped the supremacy of Ottoman. Because of the prestige of Sheikh, more Muslim soldiers defected to the Ottoman flag. When Sheikh ascended the throne in Ottoman, he once presented him with the sword "Sword of Victory", which later became a sacred gift to Ottoman monarchs.
Expansion to the Byzantine Empire
Osman has always avoided attacking his former suzerain, the Rom Sultanate. After the fall of the Rom Sultanate, because its national strength was not strong enough, he also recognized the Ilkhanate, which ruled Persia, as the suzerain, and paid tribute to the Mongolian court on behalf of the principalities of Asia Minor. The main goal of Ottoman expansion was the pagan Byzantine Empire. Byzantium, a millennium old country, was now like an old man suffering from chronic diseases. Its army was mainly mercenaries, and it was no longer supported by the crusaders in the Eastern Expedition. It fell back under the attack of Ottomans united in the name of Allah.
Dream of Europe
The Byzantine cities successively occupied by Ottomans include Eskishehir, Lefkay, Kagashisar, Inegrad and Yenishehir. He won the title of "Bey" because he defeated the Byzantine army in the Battle of Bafaernon in 1301. After occupying the city of Meronor in the northwest of Asia Minor, he renamed it Kagasisal and moved its capital here as a stronghold for further progress.
Then, Ottoman pointed to the last stronghold of the Byzantine Empire in Asia Minor, Bursa. Once he had captured Bursa, the Marmara Strait leading to Europe would open up in front of him. The siege was very hard and lasted for nine years. When the city was about to break, Osman's life came to an end.

In 1326, Osman left his son Orhan a will to "be fair, kind, cherish scholars and protect the people", and then he died. Olkhan captured Bursa and moved its capital here, burying Ottoman's body in this city. Bursa has become the holy city of Ottomans ever since. During the reign of Olkhan, the Ottoman country continued to grow. The Ottoman Empire has been on the rise for more than 300 years from its founder, Osman, to the 10th Sultan, Suleiman the Great (Timur once defeated the Ottoman Empire in the middle, but he remained strong). His successors, Olkhan, Murad I, Mohammed II, Selim I and Suleiman I, are all outstanding commanders who never emerged, making the empire's territory like a balloon bigger and bigger until the ancient Byzantium was destroyed, Proud of three continents.

In 1299, Ottoman I declared his country an independent principality.
In 1301, it attacked the declining Byzantine Empire and occupied most of Byzantine Asia Minor, where Byzantine rule was tottering. Encroached on Byzantine strongholds like Ephesus in Asia Minor.
In 1317, the Byzantine army attacked Bursa, an important town close to Constantinople, the capital of the Byzantine state, which was more heavily defended. In 1326 (the 10th year of the siege of Bursa), Byzantium gave up resistance and declared surrender until it finally lost its power to parry. But Ottoman I was seriously ill. He died shortly before moving his capital to Bursa. After his descendants moved their capital to Bursa, they buried Ottoman I in the mosque in Bursa. The successor Olkhan continued to attack the Byzantine Empire and expand abroad. It soon occupied all areas of Nicaea and Byzantium in Asia Minor.

During the Ottoman rule, the Turks gradually moved from nomadism to settled life.
Historically, in the Ottoman era, his country was still a small country on the peninsula of Asia Minor, and had just entered a stable national stage. The world empire spanning three continents is the result of the continuous efforts of his successors. However, this does not negate the influence of Osman. Without Osman, there would be no later. The rise of the Ottoman Empire has given the Islamic world, which has been torn apart since the collapse of the Arab Empire, a backbone. Moreover, because Türkiye has blocked the land route of east-west traffic, Western Europeans have to look for new traffic lines from the sea, so there is a later era of great navigation.