How often is halley's comet visible from earth? every 17 years every 100 years every 20-30 years every 75-76 years

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.