Ammianus Marcellinus has attracted more attention than most late antique histori-ans, and this interest has extended to everything from his value as a source for the government of the fourth-century Roman Empire to the literary artistry he evinces in his Res Gestae. Amongst other things, Ammianus happens to be one of our most important sources for late Roman warfare, and his significance in this regard has long been recognised. Though some aspects of his value as a military historian have attracted more attention than others, including Ammianus’ characterisation of gen-erals, gaps remain. One issue concerns Ammianus Marcellinus’ purported emphasis on the heroic general, one who led an assault, fighting from the front himself. For John Keegan, Alexander the Great exemplified heroic generalship, for he was a general wounded as much as if not more than his fellow soldiers. After Alexander, generals in the Hellenistic and into the imperial Roman world tended to eschew hand-to-hand combat themselves, though there are exceptions. By the imperial era, Ted Lendon notes that the practice had long since fallen into disuse, which made Titus’ apparent employment of just such a practice in the Jewish War all the more remarkable. Lendon has argued that this approach to command re-emerged from the fourth to the sixth centuries AD, with Alexander himself often held up as a model by the central figure of our discussion, Julian. It is this last contention that we will focus on in this chapter: heroic generalship in Ammianus Marcellinus’ Res Gestae. We will concentrate on open, pitched battles. After a brief introduction to Ammianus Marcellinus and his history, we look at how he characterises generals, especially the Caesar Julian at the Battle of Strasbourg in 358, and compare this with the depiction of the emperor Valens at the Battle of Adrianople in 378. Then we look briefly at generals in sieges before finishing with some comparative material. As we will see, the generals whom Ammianus holds in the highest regard are best considered Keegan's ‘post-heroic’ commanders, who adhere to the Odysseus ethos, not heroic generals in the mould of Alexander, who adhere to the Achilles ethos.