Ah, someone with a specific time reference. I will do till early 5c, because that is probably what you had in mind.
AD 33 - 313 the relationship between the Church and the Roman Empire was that the latter fed the members of the former to lions for sport.
313-380 the Church was tolerated by the Empire and the persecutions largely stopped.
380-410 Christianity is the state religion of the Roman Empire, then Goths sack Rome. No more empire; Europe becomes a collection of independent principalities.
97 years, out of 4 centuries, of peace. 30 years of imperial Church. The only other empire I know in Europe is the EU today. They have paganism in their constitution.
Also interesting to note, as a sidebar, that this begins the Ecumenical Councils of Christianity - the canon, trinity, etc.