Which challenges of modernity did the Ottoman Empire face during the era 1800 untile 1914?

The founder of the byzantine  empire  and its first  emperor,  constantine  the great,  movedthe  capital of the roman empire  to the city of byzantium in 330 ce, and renamed it  constantinople.  constantine  the great also legalized christianity, which had previously been persecuted in the  roman empire.

Where are the following