In the opening section of Ovid's Ars Amatoria 3 the poet, in an attempt to gain favour with his female addressees, lists a number of legends where it is men who are the deceivers. In this list he includes Aeneas, et famam pietatis habet, tamen hospes et ensem I praebuit et causam mortis, Elissa, tuae (39–40). The terms in which Aeneas' guilt is cast are striking. Aeneas is criticized not for his lover's faithlessness, but for his shattering of the rules of hospitium. At the heart of hospitium, in as much as it is friendship between strangers, lay the ideals of duty, loyalty, reciprocity, and the exchange of services, pietas (39) includes, in this context, a reference to the guest's sense of, or actual fulfilment of, the duty to pay a proper return on the hospitality received. Aeneas had a reputation for doing his duty as a hospes, i.e. as someone who was conscientious about his duty to make an appropriate return. But, according to Ovid, the return which he actually made was diametrically opposed to a proper return, and consisted of a sword and a reason for Dido to kill herself with it. Ovid's decision to frame Aeneas' guilt in terms of hospitium reflects and emphasis adopted both in his own earlier epistle from Dido to Aeneas (Heroides 7), and (what will concern us more) in the Aeneid itself. The erotic relationship between Dido and Aeneas in Book 4 of the Aeneid evolves out of the hospitium relationship established between them in Book 1. When Aeneas leaves Dido he asserts that their relationship is that of host and guest rather than of husband and wife, and that he has acted and will act well in this hospitium relationship (Aen. 4.334–9). 9). Dido, for her part, even after she has been forced to drop the argument that she and Aeneas are married (Aen. 4.431), continues to attack Aeneas and the Trojans as bad or faithless hospites (Aen. 4.538–41, 4.596–8), and ends by renouncing hospitium with them (Aen. 4.622–9).