After Caracalla concluded his campaign against the Alamanni, it became evident that he was inordinately preoccupied with the Greek-Macedonian general and conqueror Alexander the Great. He began openly mimicking Alexander in his personal style. In planning his invasion of the Parthian Empire, Caracalla decided to arrange 16,000 of his men in Macedonian-style phalanxes, despite the Roman army having made the phalanx an obsolete tactical formation. The historian Christopher Matthew mentions that the term "Phalangarii" has two possible meanings, both with military connotations. The first refers merely to the Roman battle line and does not specifically mean that the men were armed with pikes, and the second bears similarity to the 'Marian Mules' of the late Roman Republic who carried their equipment suspended from a long pole, which were in use until at least the 2nd century AD. As a consequence, the "Phalangarii" of Legio II Parthica may not have been pikemen, but rather standard battle line troops or possibly "Triarii".