Peregrinus, Petrus (c. 1220-c. 1270/90)

French scientist and scholar who published Epistola de magnete (1269). In it he described a simple compass (a piece of magnetized iron on a wooden disc floating in water) and outlined the laws of magnetic attraction and repulsion.

Peregrinus was an engineer in the French army under Louis IX, and was active in Paris in the middle of the 13th century. There he advised English scientist Roger Bacon. Peregrinus took part in the siege of Lucera in Italy in 1269.

His ideas on magnetism, based laregly on experiment, were taken up 250 years later by English physicist William Gilbert.