It wasn’t really the church entirely. It was just that 150 days is roughly the length of a standard farming season from planting to harvest. The lords and land owners didn’t need the majority of the peasants working in the winter, late fall, and early spring. There’d be nothing for them to do.

You wish feudalism returns?

Also this was not about church at all, else they would maybe not introduce serfdom on their lands and object against various form of slavery.

Holidays? What for? They couldn’t even buy funkopops checkmate commie