Codex St. Peter. c. 1200.
The art of the Medieval period is rich and varied. Artists have used a wide variety of styles and techniques ranging from textile arts to sculpture to jewelry.
The University of St. Thomas Libraries have a wealth of information in print and online about the artists and their art. For interesting discussions of the topic, head to Oxford Art Online for the introductory essays, "Illuminated manuscripts," "Gilding," "Gold," and "Mosaic."