The article discusses a passage from the “Cento nuptialis” by Ausonius where he comments upon cento technique and specifies the maximum length of a continuous quotation from the original text of Vergil. The meaning of the MSS reading et sequens cum medio is not very sound, and the author considers three proposed additions and alterations: Th. Mommsen’s et sequens <medius> cum medio (1883); L. Villani’s et sequens. Сum medio (1898); and R. Green’s unus <et unus> sequenti cum medio (1991). For better examination of these corrections, it seemed important to look at Ausonius’ own poetical practice in the “Cento nuptialis” and to compare it with two longest preserved Latin Vergilian centos: the tragedy “Medea” by Hosidius Geta (end of the 2nd century) and the “Cento Vergilianus de laudibus Christi” by Faltonia Proba (mid-4th century). In spite of some differences, all three centones show a similar tendency in the employment of the most frequent arrangements: two independent half-lines,1 independent hexametrical lines or one half-line accompanied by the following half-line in the next verse. The author believes that this can clarify the meaning of unus in Ausonius’ passage in question. Refs 18.