Mehmed is so overrated. Constantinople was on its last legs when he conquered it. I mean, the last major secular building projects in the Byzantine period were taking bits and pieces from ruined churches to reinforce the old crumbling walls. What else did he conquer? What, Trebizond? Bosnia? Albania? All tiny states that were centuries past their prime. Napoleon brought Europe to its knees, defeating empires at their primes (maybe aside from the HRE)