Among the many favours for which Ausonius thanked Gratian when he was designated consul in the autumn of 378 was ‘ad praefecturae collegium filius cum patre coniunctus’ (Grat. Act. 7). This favour, he goes on to say, preceded his nomination to the consulship, and was Gratian's own gift after his father's death; ‘et tui tantum praefectura beneficii, quae et ipsa non vult vice simplici gratulari, liberalius divisa quam iuncta, cum teneamus duo integrum, neuter desiderat separatum’ (Grat. Act. 11). This prefecture was apparently that of the Gauls (Grat. Act. 40: ‘agant et pro me gratias voces omnium Galliarum, quarum praefecto hanc honorificentiam detulisti’). In later poems he alludes to his ‘praefecturam duplicem’ (Protrept. 91), in which he was, before entering upon his consulship on 1 Jan. 379, ‘praefectus Gallis et Libyae et Latio’ (Epiced. 42).