  The issues here are complex and the historical facts are not yet well sorted out. But it appears that twentieth-century scholars who saw a close conceptual link between universal hylomorphism and the plurality of forms were perhaps thinking of the two theories as motivated by a common commitment to the first theory of predication described in § 4 above. In some cases (for example the Fons vitae), they probably were so motivated. Still, the fact that the two theories are regarded as a “pair” is a recent phenomenon, not a medieval one. It seems to have arisen first in the writings of Daniel Callus.[28]