Julius Obsequens was a Roman writer active in the 4th or early 5th centuries AD, during late antiquity. His sole known work is the Prodigiorum liber (Book of Prodigies), a tabulation of the wonders and portents that had occurred in the Roman Republic and early Principate in the years 249–12 BC. The material for the Prodigiorum liber was largely excerpted from the 1st century AD Ab Urbe Condita Libri of the Augustan historian Livy, which chronicled the history of the Roman state from its origin to the beginning of the imperial period, though Julius used it selectively and sometimes added interpretations of the omens and incidents he included. There is a common view that Julius only knew Livy's text wholly or in part from an epitome, but there is scant evidence of this.