In several works and passages, Galen reports on the model of the heart as developed by Erasistratus. Already in 1995 (published in 1997), Heinrich von Staden pointed to the parallel between Erasistratus’ model and the force pump. This technical device, which belongs to the technical apparatus developed in the frame of ancient water-supply systems, was indeed codified in textual and probably even diagrammatic form for the first time by the contemporary Ctesibius during the third century. This chapter first revisits Galen’s reports to define Erasistratus’ model of the heart technically and precisely. Subsequently, it analyzes a series of ancient works and fragments from the Hellenistic period until the second century to establish the extent to which such parallelisms are historically justified on the level of the scientific reflections of the time. In the background, the analysis of archeological findings of periods are considered to show that, contrary to what is usually assumed, the realm of practical activities and engineering might have been strongly influenced by the anatomic knowledge of antiquity.