Chapter Twenty-Eight
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chapter twenty-eight Preparing THE READER FOR war Ammianus’ Digression on Siege Engines In studies on Roman warfare Ammianus figures prominently. As a for- mer army officer, he shows a lively interest in and a detailed knowledge of military matters. His digression about siege engines (RG 23.4), which is the subject of this paper, serves to provide the necessary background information for the account of Julian’s Persian campaign. Military con- flicts between Romans and Persians in Mesopotamia invariably took on the character of siege wars, in which siege engines played a crucial role. That explains why Ammianus places his digression in the overture to the Persian campaign, although in his accounts of the sieges of Amida (19.7), Bezabde (20.11) and Aquileia (21.12) they had been mentioned several times already. The immediate cause for the digression is the re- mark about the large number of siege engines that Julian had shipped along the Euphrates to Callinicum (23.3.9). Earlier descriptions of these engines in Greek and Latin are of two kinds. There are technical treatises in which their construction is ex- plained in great detail with exact measures for their component parts. Such treatises, by Greek authors like Heron, Philon and Biton and in Latin by Vitruvius in the tenth book of his De architectura, which date from the second century BC to the first century AD, are collected, trans- lated and expertly commented upon by E.W. Marsden.1 On the other hand we find less technical descriptions of siege engines in the works of historians like Josephus, Procopius, Eusebius (FGrHist 101) and military authors like Vegetius and the Anonymus de rebus bellicis. The similari- ties between the descriptions in the Greek historians and in Ammianus at times suggest a common model, which, however, it is impossible to identify. In this paper I shall not comment on every detail of this digression,2 but focus on its technical quality, both intrinsically and in comparison with other descriptions. Ammianus treats successively the ballista (§2- 1 Marsden 1971. The English translations of passages in the digression are based partly on Marsden (p. 238 and 251), partly on Rolfe’s translation in the Loeb edition. 2 See for a detailed discussion of the digression Den Boeft et al . 1998. ammianus marcellinus 3), the scorpio or onager (§4-7), the aries (§8-9), the helepolis (§10-13) and the malleolus (§14-15). Strictly speaking, the last item does not be- long in the series, because, as Ammianus tells us himself, the malleolus is a kind of missile (teli genus), not a siege engine.3 The descriptions have in common that the author begins with the material from which the engines are made. Next, he describes them not as finished products, but as they are put together: ferrum … compaginatur (§2), dolantur axes duo quernei (§4), eligitur abies … cuius summitas duro ferro concluditur (§8), aedificatur … hoc modo (§11), sagitta … concavatur (§14).4 In this respect the digression resembles the technical treatises of Philon, Biton and Vitruvius. It would be as difficult, however, to construct these en- gines following Ammianus’ instructions as to make a living as a farmer using only Vergil’s Georgics for one’s manual. In comparison to the technical treatises mentioned above, Ammianus’ description is lacking in precision and is unsatisfactory even with regard to essential parts of the engines. It would, however, be unfair to condemn this digression because it is technically inferior to these specialised treatises. Ammi- anus clearly supposed his readers to have some idea of how these en- gines looked and worked, and his aim differs completely from that of the technical authors. His digression is first of all a literary tour de force. This is evident not only from the descriptions themselves of the en- gines, but also from the vividness with which, at the end of every single one, he relates their deadly effects. The flowery style Ammianus favours for his digressions makes the interpretation of this chapter especially difficult. First the ballista. The essential parts of this arrow-shooting engine, Vitruvius’ catapulta,5 are the bow, the stock and the slider.6 The bow is mounted on the stock, which is a long beam sticking out in front of and behind the bow. In front, the arms of the bow are stuck into vertical 3 Still, fire-brands were a regular feature in sieges; cf. e.g. Tac.Ann . 2.81.2 tormentis hastas, saxa et faces ingerere and the battle scenes in 20.11.13 (adsidue malleolos atque incendiaria tela torquentes laborabant), 21.12.10, 24.4.16, 27.3.8. 4 ‘an iron strut is fixed firmly’, ‘two beams of oak are fashioned’, ‘a tall fir is selected, to the end of which is fastened a long, hard iron’, ‘it is built in the following manner’, ‘the shaft is hollowed out’. 5 For an explanation of the terminological change from catapulta to ballista and from ballista to scorpio or onager see Fleury 1993, 226-39. Ammianus distinguishes clearly between them in 20.7.10 nec ballistae tamen cessavere nec scorpiones, illae tela torquentes, hi lapides crebros. 6 The drawings in Fontaine’s commentary volume of the Budé edition are most helpful, although, in my opinion, they are not completely correct and at times at variance with the notes in his commentary..