Funnily enough, the papacy in the 15th century forbade the use of butter in bread in Saxony. When Saxony became protestant, this silly little ban on butter was lifted. The protestant electors of Saxony just happened to be the ancestors of King Charles III. Food for thought!!

It took them FIVE popes to have their pleas answered! Pope Innocent VIII sent them a response — known as “The Butter Letter” — which granted the use of butter for their baked goods without having to pay a fine … but only for their household. The Pope was clever and put a condition in the letter stating that others could use butter for cooking, but whenever butter was used, a donation had to be made to help with the cost of constructing the Freiburg Cathedral.

https://blog.hmns.org/2013/12/the-butter-letter-butterbrief-fruitcake/