Lounsbury (Studies in Chaucer, ii. 259) objects that many scholars suppose that Valerius Flaccus was unknown previously to 1416. But, if so, how did Chaucer know that the title of his poem was 'Argonauticon Libri,' and not 'Argonautae,' as in Dares?
In fact, St. Augustine tells the whole story; De Ciuitate Dei, lib. i. cap. xix. And it was copied from St. Augustine's version into the Gesta Romanorum, Tale 135.
For lines 1896-8, Bech refers us to Godfrey of Viterbo's Speculum Regum; see the extract from it in Pertz, Monumenta Germanica, vol. xxii. p. 38, l. 159; which tells us that the teaching of philosophy and of the seven sciences at Athens was introduced there by Jupiter; see further, at p. [lvi].
We must remember that, in olden times, writers often had to trust to their memory for details not always at hand. Hence such a mistake as this was easily made.
The reference seems to be to Paulus Orosius, Hist. i. 11; but Belus is not there mentioned. Yet Hyginus (Fab. 168) has: 'Danaus Beli filius ex pluribus coniugibus quinquaginta filias habuit.' See Anglia, v. 350.