Orhan I was the second ruler of the Ottoman Empire (B. 1281 or 1288 Söğüt – D. April 1362, Bursa). Among other Ottoman Sultans, Orhan Ghazi was the only sultan whose name was of a Turkic origin. He was also known as Gazi, Şücaüddin, Seyfüddin. His father was Osman Ghazi, the founder of the Ottoman dynasty and his mother was Mal Hatun, who was the first wife of Osman Bey and the daughter of the Seljuk Vizier Ömer Abdülaziz Bey. He was the first one to earn and use title like “sultan”, “khan”, “seyfüddin” and şücâuddin”. Orhan Ghazi, also known as Sultan Orhan, got married to Nilüfer Hatun (also known as Holofira), who was kidnapped by his father Osman Bey during her wedding at Kaldırakdere and the daughter of the Byzantine ruler (Tekfur) of Bilecik. In the Ottoman dynasty, Orhan Ghazi was the first sultan to marry a foreign woman.
In 1324, when he was 36 or 43 years old, Orhan Ghazi succeeded Osman Ghazi and became the margrave of the Ottoman Principality. Orhan Bey, who was a military genius, made a name for himself in a very short time. He was counseled by Alaâddin Pasha who was a member of the ulama (T.N. a scholar class) and the son of vizier Hacı Kemâlüddin and by Alâaddin Pasha, who was his brother and vizier, by vizier Lala Şahin Pasha and by Çandarlı Kara Halil who was kadi (T.N. Muslim judge) of Bileck and then of Bursa. He owed his fame to utilizing their experiences in life. Ottoman Principality was organized during the Orhan Bey reign.
With the help of Köse Mihal, Turgut Alp, Şeyh Mahmut, Ghazi Mihal Bey and Ahi Hasan, on April 6th, 1326 he captured Bursa which he had blockaded for years and gave it to his son Murat under the name of Bey Sanjak. Thus, the capital of Ottoman Principality was Bursa, not Yenişehir. Later, upon the advices of vizier Alâadin and kadi of Bursa Cendereli (Çandarlı) Kara Halil, he was considered to have stamped Ottoman’s first coin in 1327 and it was the most important symbol for the sovereignty. However, since a coin with the image of Osman Bey was found, this judgment is no longer valid. The first mint was established in Bursa during the reign of Orhan Bey.
When the Byzantine realized that the Ottoman borders expanded through Black Sea and Istanbul, they met with Orhan's troops at the present towns of Darıca and Eskihisar, at a site then called Pelekanon. The Byzantine Emperor was wounded in the battle and the Ottomans captured İznik (T.N. then Nicaea) in 1329 or 1331. İznik was a holy city for the Byzantine and since Orhan Bey knew it, he turned a church there called Haghia Sophia into a mosque and founded Ottoman’s first university there. He assigned Scholar Kayserili Molla Davut as the principal. The Byzantine tried to re-take the city but Orhan Bey forced the Byzatine Emperor to flee. Upon this victory, Orhan Bey was called the Sultan in the Europe and Islamic worlds. Later he tried to make peace with the Byzantine. Meanwhile, he married Theodaro, daughter of the Byzantine Emperor.
After making peace with the Byzantine, Sultan Orhan headed toward Anatolia and took over a Turkish principality, the Karesids, centered in Balıkesir in 1345. He marched towards Ankara in Anatolia in 1354 and captured the city. Üsküdar was captured by the Ottomans, who expanded the borders till Çandarlı in the south when they took over the last lands of the Byzantine in the Southern Marmara Region. Uluğ Beyoğulları of Çandaroğulları joined the Ottomans, too.
When the Byzantine Emperor, the father-in-law of Orhan Bey, asked the Ottomans’ assistance against the Slavs and Bulgarians, Ottoman forces entered Istanbul on February 3rd, 1347 and left the city then. In 1347 Süleyman Pasha (T.N. his eldest son) wanted to invade Imbros but he was repelled. In 1349, Orhan Bey crossed to Rumelia for help, went until Thessaloniki and took the town back from Slavs, then turned back again. In return for his helps, the Byzantine Emperor gifted the Çimpe Castle (T.N. Tzympe or Cinbi) on the European shores of the Gallipoli peninsula to Süleyman Pasha, the commander of auxiliary forces, in order to make their cross to Europe easier. This gift meant that Ottomans then had a permanent foothold on the Rumelia legally, different from the previous transitions. The important figure in the establishment of Rumelia, Süleyman Pasha, died of an accidental fall from his horse in 1357 after he took Lüleburgaz and Çorlu. Şehzade Murat continued the conquest of Rumelia after the death of his brother, but Sultan Orhan couldn’t stand his son’s death and he died in April, 1362 at the age of eighty-one.
Orhan Bey’s state depended on second class military forces, yaya (T.N. infantry) and müsellem (T.N. cavalry) units, which were vanguards. The main reason for the formation of these forces was that those units were not always able to arrive in the campaigns in time or their success was limited for they could not maintain sieges for a long time. Instead of cavalry force of sipahis, a permanent and strong army composed of young Turkish people was needed. Another reform by Orhan Bey was Janissary and Devshirmeh system for the military forces. Murat I developed the Janissary organization and put the devshirmeh system into practice.
Even though the military system was developed through the end of Orhan’s reign and military units were built in the form of various branches of a great community, it did not last for a long time. Since the beginning of 1336, Orhan Bey had mosques, madrasahs, taverns and workhouses built and established important foundations in Bursa. Orhan Bey decupled the number of soldiers and population as well as the borders he succeeded from Osman Bey. It was accounted that there were a population of approximately 3 million and more than thirty-two thousands soldiers in the state when he passed away.
According to some fundamental sources, Orhan Bey married four different women. However, he didn’t have them as his wives all at the same time. Those wives and their children were chronically: 1) Nilüfer Hâtun (Holofira); daughter of the Prince of Yarhisar. She was converted to Islam and changed her name as Nilüfer. She was the mother of Süleyman Pasha, Murat I and Prince Kasım. 2) Asporça Hâtun, the daughter of Emperor Andronikos III of Byzantium. She was converted to Islam. She was the mother of Prince İbrahim and Fatma Sultan. 3) Theodora Hâtun; She wasn’t converted to Islam and that marriage didn’t last for a long time. She was the mother of Prince Halil. 4) Eftandise Hâtun; the daughter of Mahmut Alp.
The important scholars and scientist in the Ottoman during the reign of Sultan Orhan were; Davud-i Kayserî, a teacher at the first university in İznik, and then Alâaddin Esved (or Kara Hodja) the successor of Davudi-i Kayserî and mastermind of yaya and müsellem, Çandarlı Kara Halil, first Kadi of Bursa and Kazasker (T.N. judge of the army), Hasan-ı Kayserî and the important scholars were Seyyid Ahmed-i Kebîr-i Rufâî, Karaca Ahmet, Ahi Evran and Musa Abdal.