How long did it take for Christianity to become an acceptable religion?

Christianity gradually became an acceptable religion over several centuries. Initially, it faced persecution within the Roman Empire, but this changed significantly after Emperor Constantine's Edict of Milan in 313 AD, which granted religious tolerance. By the end of the 4th century, Christianity was established as the state religion of the Roman Empire, marking its acceptance in the broader society. Thus, the process spanned roughly three centuries from its beginnings to widespread acceptance.