Institutio Oratoria

When there is no scope for conjecture, our attention will be fixed on other points. In the first place advice will be asked either on account of the actual thing on which the orator is required to express his views, or on account of other causes which affect it from without. It is on the actual thing that the senate for instance debates, when it discusses such questions as whether it is to vote pay for the troops. In this case the material is simple.

To this however may be added reasons for taking action or the reverse, as for example if the senate should discuss whether it should deliver the Fabii to the Gauls when the latter threaten war, [*](See Livy, v. 36.) or Gaius Caesar should deliberate whether he should persist in the invasion of Germany, when his soldiers on all sides are making their wills. [*]( See Caesar, Gallic War, i. 39, where this detail is recorded, also 40 where the speech made to his troops is given. ) These deliberative themes are of a twofold nature.

In the first case the reason for deliberation is the Gallic threat of war, but there may still be a further question as to whether even without such threat of war they should surrender those who, contrary to the law of nations, took part in a battle when they had been sent out as ambassadors and killed the king with whom they had received instructions to treat.