war-engines to the emperor. There is no doubt that there was a close association between the "engineer" and the architect. The "Ten Books of Architecture" falls into the three divisions just named. The first eight books are on building, including one on water supply, the ninth is on dialling, and the tenth is on machines. Apparently he was the author of only one important building. His vision was retrospective, and, for him, architecture was based on Greek precedents.
Whence came the change from the classical spirit which sought to realise perfect types, to the Roman spirit of adventure and aggrandisement? The change, of course, was general, and "in the air," but that which best qualified the architect to deal with it was his association with military engineering.
Vitruvius in his last chapter happens quite accidentally to mention three Greek architects who were concerned in the siege of Rhodes—Diognetus, architect of the city (who had a fixed annual salary), Callias, a rival, and Epimachus, a celebrated architect of Athens, who acted with the besiegers. He also mentions Trypho of Alexandria, architect of the city of Apollonia, who, he says, saved that city by his devices. Further, we know that the most famous master of the most celebrated group of buildings in Rome, Apollodorus of Damascus, the favourite architect of Trajan, was also his military engineer, who devised the wonderful bridge over the Danube, and who wrote a book on war-engines for Hadrian. A second great architect contemporary, or a little later, Decrianus, who removed the Colossus of the Sun to another position and built the bridge and Mausoleum of Hadrian, must also have been an engineer.
At a still later time, as the records show, Anthemius of Tralles, the architect of St Sophia, and other building masters of the Lower Empire were mechanicians and engineers. Anthemius is called mechanikos. "He was an inventor of machines," we are told, and excelled in mechanical knowledge. He was employed on the fortifications of Dara.
Architects for public works were public servants (not the same thing as public servants calling themselves architects!). As late as the time of St Augustine, he mentions the city architect of Carthage, and Cassiodorus gives the form for appointing the Architectus publicorum of Rome.