  ‘Binarium famosissimum’ (= “most famous pair”) is the name given by some twentieth-century historians of medieval philosophy to what was regarded as a characteristic pair of doctrines—universal hylomorphism and plurality of forms—often maintained together by members of the “Augustinian” school of scholastics in the thirteenth century. The doctrines were opposed by “Aristotelians” such as Thomas Aquinas. The linking of the two theories under this name appears to be a purely recent development, although there are conceptual connections between the theories.