After the Ottoman conquest of Constantinople in 1453, the sultan Mehmed II ordered forced immigrations from Balkan and Anatolian cities to repopulate his devastated new capital. Although he guaranteed the immigrants abandoned Byzantine houses for free, the insufficient infrastructure in Istanbul generated a huge dissent among them. In the end, many residents fled when the government reversed the free-housing policy and levied rent on their dwellings. The angry townspeople objected, “were we brought here to pay rent for these houses of infidels?” This story reveals that, apart from the economic factors, the houses themselves also dissatisfied the new residents. How were these houses in fifteenth-century Constantinople different from the contemporary Muslim or rural domestic architecture, to such an extent that the immigrants perceived them as “infidel” and abandoned them? The survey of Istanbul in 1455 yields significant clues to answer this question regarding the architectural morphology of houses. The survey inventories 908 houses that belonged to the Imperial Treasury, with limited descriptions of the inhabitants and buildings per se. Mostly located in the peripheral neighborhoods of intramural Istanbul, these are apparently the formerly vacant Byzantine houses allotted to the immigrants, which in large part were still desolate at the time of the survey. Although the descriptions of houses are mostly bald and unavailing, such as “a single-storied house” or “a house with many rooms,” we can point out several types of buildings that the immigrants could have regarded as infidel, or at least alien to their culture of housing. Among these are renovated monasteries with multiple rooms, a kind of apartment building that was never accepted by Ottoman families until the nineteenth century. Terraced houses, which can be designated by the word “adjacent(mutassil),” are another category that was alien to the residents, due to their limited privacy and lack of substantial gardens for vegetation. Even in the later centuries Ottoman cities were predominantly occupied by spacious rural-style houses accompanied by productive gardens, surrounded by a wall. Although it is a universal phenomenon that highly urbanized and densified cities start to amass various accumulative urban dwelling units, the rustic psychology and way of living among fifteenth-century Ottoman townspeople led them to reject the “urban” congested Byzantine houses in Istanbul. The waqf property survey in 1546 indicates that after almost ninety years, the city was by and large filled with garden houses that corresponded with the residents’ mentality.