The Collaborative International Dictionary of English v.0.48:

Mediaevalism \Me`di*ae"val*ism\ (m[=e]`d[i^]*[=e]"val*[i^]z'm),
   n.
   The method or spirit of the Middle Ages; devotion to the
   institutions and practices of the Middle Ages; a survival
   from the Middle Ages. [Written also medievalism.]
   [1913 Webster]