Just start at the very beginning, underground Christian art. Then its rise in popularity.
http://www.huntfor.com/arthistory/medieval/earlychristian.htmhttp://arthistory.about.com/od/medievalart/Medieval_to_Early_Renaissance_Art.htmThen the Dark Ages. Important fact--Dark Ages art is ass ugly because of Christian ideals.
http://www.usask.ca/antiquities/Collection/Medieval_Art.htmlThen go on about how the church sponsored pretty much all the art of the renaissance.
Our buddy Masaccio
http://en.wikipedia.org/wiki/Masacciosaid FUCK THAT to shitty dark ages art and started trying to paint realistically.
also, this:
http://www.wga.hu/Maybe work Antoni Gaudi's cathedral in at the end. Almost every art movement had roots in the church somewhow. The major examples of each achievement will include church-sponsored art. This went on until this century, when elaborate photo realistic art fell of favor.
Salvador Dali did illustrations to an edition of Dante's Inferno.
Antoni Gaudi's cathedral
http://www.archiplanet.org/buildings/Sagrada_Familia.htmlBurne-Jones and his stained glass windows
http://www.liverpoolmuseums.org.uk/picture-of-month/displaypicture.asp?venue=7&id=105http://www.victorianweb.org/painting/bj/glass/flygare7.htmlAnd then there's always modern art like Piss Christ and the portrait of Mary with elephant shit as a nipple.