The correct answer is the ottomans.
The byzantine empire or also called eastern roman empire, originated in the year 395 d.c.
The byzantine empire managed to survive the germanic threat lasting almost ten centuries, until the year 1453 when the ottoman turks occupied their capital.
The fall of constantinople, which took place on may 29, 1453, could only be the chronicle of an announced death. The disintegrated byzantine empire, once indestructible, had begun its decline some time ago and the inexorable advance of the ottomans, who had conquered huge territories in asia and north africa at the height of the fifteenth century, found no great opposition in them.
However, its fall was a real shock to the christian world, which saw how the doors of europe would have been for the ottomans.
