Church holidays or holy days were very frequent in the middle ages. Here is one link Medieval Holidays that testifies this:
"The rural population of the Middle Ages had their days of rest and amusement, Middle Ages holidays were then much more numerous than at present. At that period the festivals of the Church were frequent and rigidly kept, as each of them was the pretext for a forced holiday from manual labour."
My understanding has been that the Roman Catholic Church levied heavy fines upon those landowners who worked the land on these days. Were many large landowners in Germany and elsewhere motivated by avoiding frequent Church holidays as they supported the reformation?