The first stage in the life of the state is the "Establishment" period. These two phases, which lasted from the beginning until the conquest of Istanbul in 1453, could have been completed earlier if Timur had not dealt with Yıldırım Bayezid in Ankara in 1403.
Osman Gazi, who was the first ruler of the Ottoman state, became eternal as the founder of a world-class state in history, thanks to his high intelligence and endless efforts, although he inherited only one clan chieftain from his father.
His son Orhan Gazi greatly enlarged the Ottoman country he inherited from his father. During the reign of Orhan Gazi, the capture of Bursa was an important move and this city was made the center of the Ottoman state. The establishment of the first administrative, judicial and military institutions and organizations for the organization of the state with an important event such as the transition of the Turks to Rumelia was in his time. The service of Orhan Gazi's brother, Alaeddin Pasha, and the Çandarlı family is important in organization and administration. During the transition to Rumelia in 1356, the efforts and services of Orhan Gazi's son Süleyman Pasha are especially worth mentioning. The transition of the Turks to Rumelia is the first evidence that the Ottoman state will not remain only Asian and may become universal in the future.
During the reign of Murad Hüdavendigar, the first sultan who died on the battlefield, the Ottoman state fought battles to defeat the combined forces of the Europeans, which now show the scene of a crusader army, on the occasion of the Balkan conquest. The pitched battle in the Kosovo plain in 1389 is such a war. With the first Kosovo victory, the first major obstacle for Balkan domination was overcome. Kapıkulu military organization was also established for the first time during the reign of Murad Hüdavendigar.
The Battle of Niğbolu (1398), won by Yıldırım Bayezid, and the victories of the Second Murad in Varna (1444) and the Second Kosovo (1448) are also wars won against the allied Christian forces, which are also a crusader army. Thanks to the brilliant successes achieved in these momentous wars, the foundations of the Turkish domination that will continue for several centuries in the Balkans were strongly laid.
As the most fervent ruler of the founding period, Yıldırım Bayezit won successive victories in Anatolia and Rumelia, the Ottoman state faced a great danger when the Byzantines were heavily besieged by besieging Istanbul. This danger; It was Timur who continued the invasion movements in the west direction after establishing a great state in Transoxiana. Lightning Bayezit 140? was defeated in Ankara's Çubuk plain and was captured by Timur; The Ottoman state survived the danger of collapse. Timur not only captured Bayezid during the Ankara battle, but also destroyed the Anatolian Turkish unit that Yıldırım had established after long efforts. Because Timur put the Anatolian lords in charge of their former principalities. Meanwhile, the reign fights between Yıldırım's sons after the Ankara war for ten years (1402-1413) were also very harmful and shocking for the state.
When Çelebi Mt Imet, who acted as the most diplomat of Yıldırım Bayezid's sons, finally took the throne of the Ottoman Empire alone; It has succeeded in eliminating Timur's destructive influences and bringing the Ottoman state to its position almost before the Battle of Ankara. Thus, just as Osman Gazi was the first founder of the Ottoman state, Çelebi Sultan Mehmet was rightly the second founder by preventing Timur's policies and movements aimed at breaking up this state and ensuring unity.
From the first days of the establishment of the state, the Ottoman sultans, while making conquests in Christian countries on the one hand, also sought to gather Anatolian Turkishness under one flag. Obtaining Turkish unity in Anatolia was undoubtedly not easy, and in general, an armed struggle was required with the Turkish principalities for the acquisition of this goal.
The Ottoman Empire completed its establishment and security in 1453 with the power and skill of the first sultans in commanding, statesmanship and organization. The importance given to the military order while the state was newly formed is the result of victories even in the face of mighty adversaries; The just and worthy administration has also been the reason why foreign races easily warmed up to Turkish rule.
When Fatih Mehmet, the first ruler of the ascension period, conquered Istanbul in 1453, the places up to the source region of Kızılırmak in Anatolia, except for the land of Karamanoğulları; "In Rumelia, it included the whole of Thrace and Bulgaria, and a part of Greece and Serbia.
Consequently, the foundation period lasted for one and a half centuries; Conquest in Christian countries is the period in which the main laws, various state and country institutions and institutions were introduced and improved following the development of the state, together with the movements to unite Anatolian Turkishness under the Ottoman administration.
