latrocinio, 'brigandage' opposed to 'bellum,' [§27]. 'Latro,' originally 'a mercenary,' connected with λατρεύω; hence a brigand, because mercenary troops were addicted to indiscriminate plundering.
sciam, subjunctive, as giving a reason, 'seeing that I know you have sent on,' etc.
Forum Aurelium, a small place on the Via Aurelia, about fifty miles from Rome.
cui. See [note on 1. 16].
aquilam. Marius introduced the silver eagle as the standard of the legion. The one in question had been used (according to Sallust) in the war against the Cimbri.
cui domi tuae, etc. The place where the eagles were set up in the camp was regarded as sacred. Catilina prepares a similar sacred spot for his in his own house. Sacrarium means (1) a shrine, (2) any secret place; it is here used in both senses; hence trans. 'for which you have consecrated at your house the secret chamber of your crimes.' But Halm would omit 'scelerum tuorum' as an interpolation.
tu ut illa, etc. See [above on §22].
altaribus, 'the altar'; the singular form is not found in classical Latin.