The “vision” of Constantine, as recorded in Lactantius’ De mortibus persecutorum 44.5–6 and in Eusebius’ Ecclesiastical History 9.9. 2–10, has been debated at length. The basic difficulty in these accounts lies in their presumed Christian bias. The inscription on the Arch of Constantine, however, provides a government-sanctioned record of the “vision” from a predominantly pagan viewpoint. The expression instinctu divinitatis on the arch has been linked to the phrase instinctu divino in Panegyrici Latini 12.11. 4 (delivered in 313). It seems, however, that the proximate source is the phrase instinctu deorum from the account by Florus (Epitome 1.3. 1–2) of the expulsion of the “tyrant” Tarquin the Proud. The ultimate source appears to be the concept of instinctu divino as explained in Cicero’s De divinatione [End Page 647] which became a “text” for foreknowing the will of the gods. The connotation of the phrase was preserved into late antiquity, not only by the continued study of Cicero but also through such authors as Livy, Seneca, the panegyrists, and Lactantius. Constantine demonstrated his knowledge of Cicero’s text in a speech given in 324. The senate’s appropriation of this term for the arch-inscription suggests that even pagans may have accepted some version of the “vision” of Constantine as early as 312–315.