At the time of Augustus, the Greek geographer Strabo considered cataphracts with horse armor to be typical of Armenian, Caucasian Albanian, and Persian armies, but, according to Plutarch, they were still held in rather low esteem in the Hellenistic world due to their poor tactical abilities against disciplined infantry as well as against more mobile, light cavalry. However, the lingering period of exposure to cataphracts at the eastern frontier as well as the growing military pressure of the Sarmatian lancers on the Danube frontier led to a gradual integration of cataphracts into the Roman army. Thus, although calvarymen with armor were deployed in the Roman army as early as the 2nd century BC (Polybios, VI, 25, 3), the first recorded deployment and use of cataphracts ("equites cataphractarii") by the Roman Empire comes in the 2nd century AD, during the reign of Emperor Hadrian (117–138 AD), who created the first, regular unit of auxiliary, mailed cavalry called the "ala I Gallorum et Pannoniorum catafractata". A key architect in the process was evidently the Roman emperor Gallienus, who created a highly mobile force in response to the multiple threats along the northern and eastern frontier. However, as late as 272 AD, Aurelian's army, completely composed of light cavalry, defeated Zenobia at the Battle of Immae, proving the continuing importance of mobility on the battlefield.