ABSTRACTThe fourth-century Rudston ‘aquatic’ mosaic is likely to show Oceanus at the centre rather than Neptune, and the dominant position of the head on the floor suggests that the inspiration for it derives, however remotely, from North African models where the scene was common. This is made more plausible by the fact that African influence, as is well known, is also detectable on the famous Venus mosaic by the same mosaicist in an adjacent room in the same building. At Brading, the central figure in the main reception room – a half-naked man with stick, globe and sundial – is identified, not just as a generic ‘philosopher’ type, but specifically as the third-century B.C. astronomer and poet, Aratus, on the basis of comparanda on mosaics, tapestry, silverware and in an illustrated manuscript of his work, thePhaenomena. It is further suggested that the key to reading the damaged larger part of the Brading floor above Aratus might be a Latin translation of his work, possibly that by Avienusc.A.D. 350, if the mosaic is indeed approximately of that date rather than earlier, and that the subject-matter of the panels alluded to constellations described in the poem. A very tentative attempt is made to identify what might have been depicted in the panels, on the basis of the mythology behind the constellations as explained in Latin adaptations of the poem: those of Perseus and Andromeda are illustrated in the surviving panel, and possibly Phaethon and Eridanus, Hercules and the serpent in the Garden of the Hesperides, and conceivably Pegasus at a spring were shown in the other three. It is also suggested that these unusual scenes might have been based on an illustrated manuscript of the work in the possession of thedominusat Brading. Be that as it may, the mosaic does appear to provide further evidence of the depth of classical learning displayed by at least some members of the Romano-British rural élite in the fourth century A.D.