"Ars Memoriae" (Latin for Memory Art)

Used by Ancient Greeks and Romans from as early as 500 BCE, this remarkable and extremely effective method was recovered during Renascence. But, around the late 16th century, knowledge and use of this method steadily declined due to accusation of being impious because it was thought to excite absurd and obscene thoughts.  It was also argued that it was further suppressed during the Reformation and Counter-Reformation when Protestants and reactionary Catholics alike worked to eradicate pagan influence and the lush visual imagery of the Renaissance.

Basically, it is a method of memory enhancement which uses visualization to organize and recall information. 
Association of emotionally striking memory images within visualized locations and the association of text with images.

http://www.wikihow.com/Build-a-Memory-Palace
http://www.memory-sports.com/memory-techniques/