This paper contains a detailed analysis of the final epistle of Tiberius Claudius Donatus’ Interpretationes Vergilianae, addressed to his son Donatianus. Through a comparison with Verg. Aen. VII 641-646 (and Donatus’ interpretation of these lines) it is possible to argue that Donatus was envisioning this epistle as the conclusion of a long work (the commentary itself) and the starting point of a new endeavour: the writing of a thirteenth book covering all the Realien of the Aeneid.