Medieval art is usually classified into a few categories: Early Christian, Migration Period Byzantine, Insular, Pre-Romanesque/Romanesque and Gothic. Because each location in which medieval art was being created was attempting to become an independent nation, there are subsects of each category found in each group because of the differing cultures and histories found in each region.
The primary mediums for medieval art were sculpture, illuminated manuscripts, stained glass, metalwork and mosaics. Interestingly, small decorative artisan pieces were considered more valuable than monuments during this time. When I think about the connection between the categories of art and the mediums used it makes sense; in the Early Christian art we find the widespread use of complex and beautiful stained glass windows in churches as religious symbols and Migration Period art would value small, decorative pieces because they were easy to carry and retain value around when people were still nomadic.
The most famous medieval art is found in Europe. For example, stained glass windows: 
this makes sense even today because of the importance 
Christianity played in Europe. Even today you can visit churches in Barcelona and France to see beautiful stained glass windows. The same applies with Romanesque & Gothic art in architecture. Throughout Europe there are buildings both types of structures.
nice pictures