An earlier De Motu Cordis.

Thirteenth century medical science, like medieval scholarship in general, was directed at reconciliation of Greek philosophy/science with prevailing medieval theology and philosophy. Peter of Spain [later Pope John XXI] was the leading medical scholar of his time. Peter wrote a long book on the soul. Imbedded in it was a chapter on the motion of the heart. Peter's De Motu was based on his own medical experience and Galen's De Usu Partium and De Usu Respirationis and De Usu Pulsuum. This earlier De Motu defines a point on the continuum of intellectual development leading to us and into the future. Thirteenth century scholarship relied on past authority to a degree that continues to puzzle and beg explanation.