The Internal Palace

The one most common method used by the Greeks to achieve this purpose was the mental construction of a memory palace. ... To become the student of a reputable teacher, the pupil had to prove that he was at home and at ease in some vast architecture that existed only in his mind, and within which he could move at an instant to the spot of his choice. Each school had its own rules according to which this edifice had to be constructed. It had to contain several visually distinct classes of features such as columns, angles, rafters, rooms, archways, niches, and thresholds.


Ivan Illich, In the Vineyard of the Text, 1993