Monks of course. Think about it. During the dark ages the monks preserved much of the knowledge of western civilization. The image of a monk working over his illuminated manuscript is familiar, but that wasn't their only contribution to culture. Monasteries were places of both prayer and a wide variety of work. The monks experimented with agricultural techniques and animal husbandry, use of medicinal herbs, etc. They built irrigation and drainage systems. They shared their knowledge with the peoples around them and, when the various monastic communities met for their annual meetings, they swapped discoveries and new ideas. These quickly spread throughout western Europe. The monks also took care of the poor and sick in their communities and, in fact, England had no need of poor houses until the monasteries were stripped, the religious orders dispersed, and their properties confiscated during the Protestant revolution. There's a wonderful book by William Cobbett (The Protestant Reformation) written in 1821 that details, among other things, the horrors brought about by the destruction of the religious orders in England. Read the introduction here. What a gift the monasteries were, not just to the Church, but to society and culture.
I remember reading an inspiring poem in my eight grade poetry class by Henry Wadsworth Longfellow called The Legend Beautiful. It tells of a monk who, in the midst of an apparition of Christ, hears the chapel bell calling him to feed the poor at the gate. He struggles with his desire to stay and worship and his responsibility and finally decides, "Do thy duty; that is best; Leave unto thy Lord the rest!"
When he returns after dispensing food to the beggars, he marvels to find Christ waiting for him. Jesus tells the dutiful monk, "Hadst thou stayed I must have fled."
The Lord is still calling men and women today to religious life. One inspiring new monastery is in Wyoming where a handful of young men(and I do mean young) are answering the call to form a New Carmel. You can take a virtual visit of their monastery and share in their work by (and now for the commercial) purchasing their own secret coffee blend. It gets high marks from Coffee Review. Check it out. Isn't there someone on your Christmas list who would enjoy their Christmas coffee? It's only available for a short time.