Turks and Ottoman Tribe; The Turks had stepped westward with an adventure of 900 years with the migration movements starting from Inner Asia, some of them reached to the east of Europe , some of them made the Caspian Sea into a Turkish lake and some of them reached the Anatolian borders earlier than the Seljuks. But none of them could hold on to Anatolia with a definite and irrevocable victory like Sultan Alparslan. After the epic victory in 1071, Alparslan the great ruler of the Seljuks opend the gates of Anatolia to Turkish territory and could step into the final destination of the immigration adventures that continued westward because of the demographic and political turmoil of Inner Asia. The Turkish tribe, who could not hold in Inner Asia, was flocking to Anatolia years ago to get away from conflict with the Muslim states of Iran, Irag, Syria and to seek new and more prosperous homeland after the collapse of Great Seljuk State. And years later, the establishment of the Ottoman Empire or rather establisment of the Ottoman seigniory, began with the death of Ertugrul and the collapse of the Anatolian Seljuk State.While the Anatolian Seljuk State was demolished, the principals who ruled Anatolia were trying to determine their destiny and to secure their assets in the region. In this period the Kay?lar were not as strong as they had ever been able to established good relations with the neigboring Byzantine tectonics of Sö?üt Which was given to them as a homeland. The establishment of the Ottoman seigniory took place during the reign of Osman who replaced Ertugrul Gazi after his death. Kay? tribe was a very calm and prosperous region when they settled in Sogut, their new home. The Byzantine state ruled the territories outside of Istanbul by border governors. Sögüt, ?negöl, Karacahisar and Bilecik constituted the border of the Seljuks State in the middle of the monuments. fuedal landlord of Karacahisar and Bilecik had been living well with the Seljuk State for a long time, paying taxes and continuing their existence in the region depending on Byzantium without any hostility. After the death of Ertu?rul Gazi, Osman became the new manager of the state. Normally, Saru Yacht would become the ruler but Saru Yacht died in Domanic war.Establishment of Ottoman Empire; The Anatolian Seljuks Sultan III. Alaeddin Keykubad was brought to Iran by Ilkhanians and was founded in 1299, proclaiming independence because of the resultant authority gap. Fall of the Ottoman Empire; In my opinion, the largest of the decadent causes of the Ottoman Empire was the centralized management system. It is a form of one-man administration. When a Sultan died, the son of the Sultan sat the throne. It had been like this for years, in fact the biggest strike to Ottoman Empire was done by throne wars. Because the crown princes started the secret throne fights before their father died and many of them became fratricides after their father died due to sitting the throne. 1- Internal CausesThe religion factor, which at the beginning was used as a driving force in the foundation of the state, has had important influence on the collapse due to the difference of interpretation. In particular, the class of clergy who emerged in the name of Ulema acted like a Catholic Church in the West. This led the state to a demolition in all areas, especially in the field of education.The people who ruled the state initially consisted of Turkish people. After Fatih Sultan Mehmed, when the servants began to be used with the Devshirme system, separation started between the nation and the state.The initial surplus of income declined for various reasons and economy deteriorated considerably. When the economy broke, the soil system broke. Immigration had begun due to population growth and deterioration of the land system. This had a negative impact on internal security.Anatolian people lived comfortably because there was no problem with the state at the beginning. However, as the taxation on the resultant people which ruined the order of the land, increased , the people either left the land or chose the way of uprising by unificaiton of the villagers in the periphery. This situation caused Anatolia to become a bloodbath.2-External ReasonsThere was a significant development in Europe when the Middle Ages ended. With Renaissance and Reform, Europe became the new locomotive of world civilization and began to produce technology. A great improvement was made in the development of gunpower, clock, paper, compass, printing press brought from the East. The establishment of the strong states in Europe, the turmoil in Europe and the emergence of small states during the rise of the Ottoman Empire had a positive impact, but later on large and medium sized and deep rooted states began to be established. The Holy Roman Empire began to pose a threat to the Ottoman State as strong states such as the Roman Empire, the Kingdom of France, the Russian Empire of the Austro-Hungarian Empire, the Kingdom of England, and the Kingdom of Spain. From the results of the Renaissance and the Reform, the sea explorations again negatively affected the Ottoman Empire. New continents and new habitats of the world were discovered by the sea and the rest of the population of Europe was relieved by sending them here, and European states obtained gold and silver from these places. Resources from newly discovered places have been evaluated inside and the development has been accelerated. The availability of sea routes has simplified the way to the east and facilitated the purchase of goods.The French Revolution, the Renaissance reform movements in Europe and the developments that have taken place as a result of the discoveries have accelerated the brain development of the European people and made significant improvements in the field of human rights. A revolution had been realized in Europe led by the urban French as a result of the enlightenment revolution especially in France. This revolution in France had not affected the only French , the political ideas of this revolution would affect the whole world. This affected the world as well as the multinational Ottoman State. The nations in the imperial structure started to rise and the process of demolition of the state has been accelerated. The economic privileges given to the European states by the Ottoman State in order to reorganize and balance the economic situation have become a way of exploiting the Ottoman Society in the later period, and not just forensic financial areas that are not in the economic field. The political independence of this state was hit by bigger bumps in the later period.