This paper analyses the solitary instance of a monumental Latin inscription in De architectura. Attributed to one Diognetus of Rhodes near the end of end of the treatise, the inscription is almost surely a Vitruvian invention, as is the narrative in which Vitruvius embeds it (cf. Plu. Demetr. 21). In combination, both the inscription and its context offer a powerful and a literal example of the recent suggestion (Lowrie 2009) that successful Vitruvian monuments are in some sense 'legible.'
According to Vitruvius, the (otherwise unknown) Diognetus defeated Demetrius’s massive siege-engine known as the helepolis (“city-taker”) at Rhodes. After this success, Diognetus dragged the helepolis into the city and inscribed it: ‘Diognetus e manubiis id populo dedit munus’ (Vitr. 10.16.8). Vitruvius records Greek inscriptions elsewhere in De architectura; that he attributes this singular Latin inscription to a 4th c. Rhodian therefore gives the lie to its historicity and instead suggests an exemplum for a Roman audience (cf. Vitr. 1.1.5-6 with Romano 2011 and Oksanish 2011). But if there is lesson here, what is it?
Again, text and context provide clues. By transforming the helepolis from a machine into a monumental ‘munus e manubiis,’ the inscription complicates an episode already noted for its problematic assimilation of an architectus to an imperator (König 2009 and Cuomo 2010). Remarkably in a book devoted to machines, Diognetus saves his city not with a technical counter-measure, but with his skill as a commander (sollertia), while his claim to have given the machine ‘e manubiis’ usurps the prerogative of a victorious general. A distinctly Caesarian ablative absolute intensifies this claim to imperial authority (Vitr. 10.16.7 his…constitutis; cf. Caes. BG 4.13, 4.23, etc.), but intimations of the architect’s role as an author should not be minimized: Diognetus’s designation of the machine as munus recalls the composition of De architectura itself, which Vitruvius describes as munus at the treatise’s midpoint, 6.Pref.7.
The primary aim of De architectura qua munus is the fulfilment of Augustus’s desire for durable and proportional representation of his r/Res g/Gestae (1.Pref.3, animadverti multa te…aedificiorum pro amplitudine rerum gestarum ut posteris memoriae traderentur curam habiturum). The posteris tradere ‘formula’ hints that such monuments are in some measure legible (Vitr. 7.Pref., Liv. Pref., Tac. Ag. 1.1 and 46.4, and numerous inscriptions; see also Lowrie 2009); Diognetus’s helepolis-inscription makes much the same point, but in somewhat different terms and with radically distinct consequences. For whereas in Vitruvius’s dedication the mimetic success of monumental legibility underpins a mutually advantageous relationship between architect and patron, the Diognetus-inscription in the penultimate chapter hints at something more antagonistic, albeit equally focused on the view from posterity.
Indeed, helepolis-episode as a whole implicitly chastises the Rhodians for their unfair treatment of Diognetus, a native son. Prior to their hour of need, the Rhodians had dismissed Diognetus, who returns only when the Rhodians agree to grant him the helepolis if he is successful. Thus, the inscription is less a memorial to the enemy’s defeat than it is a commemoration of Diognetus’s success and, indeed, the Rhodians’ folly. The stakes of that folly are raised further by a Rhodian law cited at Vitr. 2.8.15 forbidding the removal of dedicated trophies. The durability of Diognetus’s text – like that of all ‘legible’ monuments – is thereby ensured, as is a cautionary tale for those doubting architectural expertise and its power to shape history.