The University of Caen Normandy’s interactive virtual model of ancient Rome for both education and research started in 1994 and has developped a fully interactive model of ancient Rome that includes its architecture, machinery, political and social life . Virtual reality, with its immersive and interactive potential has made this impressive 3D restitution possible. This conference will combine a three-dimensional virtual tour in Constantine’s Rome with the presentation of a series of military inventions. A manuscript preserved in the Middle Ages in the cathedral of Spire, in Germany, has provided a mysterious anonymous treatise entitled De rebus bellicis (On military affairs) from the end of the 4th century AD. The author offers the emperor monetary and fiscal reforms as well as technical innovations for military equipment. Some of these innovations appear to be genuine inventions such as the ox-powered paddlewheel boat or the chariot à faux, a driverless cart equipped with automatic whips. The machines were reconstructed from the original text and drawings of the author found in the De rebus bellicis manuscript. The presentation includes an interactive virtual tour to see the machines in context with technical details of how they worked.