[baud147258]

Regarding the catholic Church, one could make the argument that it helped preserve and translated Antic texts in the monasteries. And there are a few point on which society regressed in the Middle Ages: human trafficking for slavery disappeared in the Middle Ages (but not slavery, since one could argue that serfdom is a form of slavery) and reappeared in the age of enlightenment; the place of women improved during that time too.

[ivanhoe]

Church also played important role as a base for scholars, giving smart people the basic education and a chance to live without having to work hard to survive, so they had time to study and learn and think. However, in the beginning monasteries did preserve some knowledge, but severely filtered and censored selection. Also there wasn't that many books there as one might think. When Toledo fell back into the hands of Christians in 11th century its library had (significantly) more books than all of the West Europe together. Only after that the effort on translating books really took off, the first Universities started forming, and the shapes of new civilization started to take shape again.