http://en.wikipedia.org/wiki/Art_of_memory

Techniques commonly employed in the art include the association of emotionally striking memory images within visualized locations, the chaining or association of groups of images, the association of images with schematic graphics or notae (”signs, markings, figures” in Latin), and the association of text with images. Any or all of these techniques were often used in combination with the contemplation or study of architecture, books, sculpture and painting, which were seen by practitioners of the art of memory as externalizations of internal memory images and/or organization.

http://www.mnemosyne-proj.org/