Christianity emerged as a political force in Western Europe during the late 4th and 5th centuries. The Edict of Milan (313 AD), issued by Emperor Constantine, legalized Christianity, paving the way for imperial conversion and the faith's integration into state affairs.
During the Middle Ages, the Pope wielded significant influence over European politics, often mediating disputes. The close Church-state relationship fostered theocratic elements, evident in the Holy Roman Empire and French monarchies.
By the late 5th century, Christianity was firmly entrenched as a political power, shaping governance, law, and society across Western Europe.