The _Syrtes_ were two great gulfs on the north coast of Africa.
For Scylla and Charybdis, see note on Book III stanza lv.

The Lapithae were a Thessalian tribe, ruled by Perithous.

The Centaurs came to his marriage feast, and at the instigation of Mars, fought with the Lapithae until the latter were defeated.

'Diana's ire' was caused by neglect on the part of king Oeneus of Calydon to sacrifice to her.
She sent a wild boar to ravage the country.
LXIX.

'Trivia's lake' refers to the little lake of Nemi.