Prou, [143]

Ptolemy, [54], [78]

Putnam, [103]

Pythagoras, [63]

Pythagorean numbers, [13]

Pytheas of Massilia, [76]

Rabbi ben Ezra, [60], [127]

Radulph of Laon, [60], [113], [118], [124]

Raets, [62]

Rainer, see Gemma Frisius