Virgilius wrote at least two surviving works, the "Epitomae" and "Epistolae". The number of books in both groups – 12 and 8 (though the last surviving Epitoma may have been numbered 15, implying there were once three more books now lost) – compares to the number of books in Donatus "Ars Maior" and "Ars Minor". He displays knowledge of authors such as Isidore of Seville, Virgil and Aelius Donatus, but never quotes them by name. Instead one finds in his works a plethora of obscure and unlikely-sounding authorities mentioned nowhere else and quotations attributed to well-known authors which cannot be identified in their writings. Thus there are Varro, Cato, three Vergiliuses, three Vulcans, Aeneas and Origenes, and also Sufphonias, Galbungus, Sagillus, Blastus, Gurgilius, Balapsidius – the list can be expanded. Some of these names are clear fabrications, often displaying considerable knowledge of classical and patristic literature.