Early Christian Symbols  http://www.catacombe.roma.it/en/symb.html

Book Of Kells Prints http://www.snake.net/people/paul/kells/thumbnails

Early Christian Art http://www.ou.edu/class/ahi4263/frameset.html

History Of Art http://www.ou.edu/class/ahi1113/html/ch-07-2.htm