The Catechism in Questions & Answers

602. What important developments occurred in the Christendom of the nineteenth century?

The so-called “revivalist movements”— which became especially popular among Protestants in England and the USA—were also of great significance: believing Christians appealed for people to turn away from “cultural Christianity” and return to a living Christian faith. This call for reflection on the gospel was often associated with the hope in the return of Christ.
This is the historical context in which God prepared for the renewed activity of Apostles.