Many lists of "wonders of the world" are said to have existed during the Middle Ages, although it is unlikely that these lists originated at that time because the word medieval was not even invented until the Enlightenment-era, and the concept of a "Middle Age" did not become popular until the 16th century. Brewer's refers to them as "later lists" suggesting the lists were created after the Middle Ages.

Sources:

http://wonderclub.com/WorldWonders/MedievalWonders.html

http://keralaarticles.blogspot.com/2007/12/seven-wonders-of-medieval-world.html

http://www.newworldencyclopedia.org/entry/Seven_Wonders_of_the_World

http://channel.nationalgeographic.com/