How many centuries did Christianity spread to Western Europe?

Theoretically, the spread of Christianity in Europe began at the beginning of our era, in everyday life the expression “from the birth of Christ”, ie. with 1 AD.

If we are talking about Christianity as the dominant religion, then this began in the 3rd century, during the reign of Emperor Constantine. In 380, a decree was issued in the Roman Empire, affirming Christianity as dominant.

After the fall of the Roman Empire, the re-establishment of Christianity took place in the 6th century, after its adoption by the Franks, who then dominated Western Europe.