The proliferation of writings of all sorts, in government as much as in the schools, made reliance on identifying material solely by mental indexing less effective. The psalms might be learned by heart, but the accumulating mass of glosses on them could not. Similarly no archivist could find his way through the hundreds of membranes in the royal pipe rolls, plea rolls or memoranda rolls. To help him in his philosophical reading at Oxford around 1230, Robert Grosseteste devised a system of about 400 symbols, which he placed in the margins of texts to indicate different subject matter. An upturned 'V', for example, indicated references to 'God's wisdom' and a crescent moon pointing to the left indicates 'the dignity of man'. Unlike the croziers, mitres, and other illustrative symbols used by Ralf de Diceto and Matthew Paris, Grosseteste's signa are abstract in form: intersecting lines, patterns of dots, and the like. They are comparable in appearance with masons' marks and other tradesmen's signs. In terms of Ciceronian memorizing techniques, however, Grosseteste's signa are 'images' as much as those of Ralf and Matthew: Grosseteste located them on the pages he read in order to map his path through the thicket of scholastic texts.From Memory to Written Record, England 1066-1307, M. T. Clanchy, pg. 179
This is fascinating. I'm surprised Grosseteste doesn't pop up more in articles on hypertext or social tagging, since this is such a clear historical example. Does anyone know where I might find a scan that shows Grosseteste's symbols in action?