The first sentence of Hyginus' Prometheus is:
Hominés anteá ab immortálibus ignem petébant neque in perpetuum serváre sciébant; quod posteá Prometheus in ferulá détulit in terrás, hominibusque mónstrávit quómodó cinere obrutum servárent.
Before, people sought fire from the immortals and didn't know how to keep it continuously [lit]; quod afterward, Prometheus brought it down to earth on [the end of] a fennel stalk and showed people how to keep it buried in ashes.
What is quod doing here? It doesn't seem to be a relative, it doesn't seem to be "since," it doesn't seem to be functioning adverbially. I realize Hyginus is hardly the stylist's stylist, but it's still bugging me.