In early period of Ottoman Empire, vizier had an indisputable place. Viziers, especially after the conquest of Constantinople in 1453, liberated the empire, which started to be organized in the region of Bithynia, from the traditional Turkish Principality identity as well as its organizational structure. For this reason, it is not a coincidence that in the first period (1299/1302-1453), when poets like Ahmedi were sometimes satirized, the Ottoman Viziers were mostly dealt with in terms of their institutional aspects. Likewise, as researchers have revealed since the first years of the republic; while the Ottoman Viziers occupied important political positions in the Turkish states organized in Central Asia and Eastern Europe, they not only fulfilled the duties and responsibilities of these political positions, but also took initiatives to meet the military and parallel financial needs of the expanding empire. Undoubtedly, the most striking of these are the formation of the janissary corps and the financial system depending on it. On the other hand, there is no doubt that the military and financial revolutions that formed the cornerstone of Ottoman expansionism overshadowed the diplomatic mission of the viziers. Such that even in Fatih's Law, there are few clues regarding this issue, which is considered as the cornerstone of the institutionalization of the empire. The aforementioned code states that the vizierate is the most important position after the emperor, but this position is still an authority that is subject to control by various independent bureaucrats. However, the diplomatic mission of the viziers is uncertain in the early Ottoman perform works or studies, as in the royal decree. The aim of this perform works orstudies are to evaluate the first period Ottoman viziers with their diplomatic missions in the context of the conquest of Constantinople.
Keywords: Ottoman Empire, Grandvizier, Viziers, Byzantine Empire, Istanbul, Constantinople