From Chapter 14 of the Decline & Fall

* Valeria quoque per varias provincias quindecim mensibus
plebeio cultu pervagata.* — Lactantius de M. P. c. 51. There is
some doubt whether we should compute the fifteen months from
the moment of her exile, or from that of her escape. The
expression of *pervagata* seems to denote the latter; but in
that case we must suppose that the treatise of Lactantius
was written after the first civil war between Licinius and
Constantine. See Cuper, p. 254.