§413. Uses of the Ablative As Instrumental

Accompaniment is denoted by the Ablative, regularly with cum:—

• cum coniugibus ac līberīs (Att. 8.2.3), with wives and children.
• cum funditōribus sagittāriīsque flūmen trānsgressī; (B. G. 2.19), having crossed the river with the archers and slingers.
• quae supplicātiō sī cum cēterīs cōnferātur (Cat. 3.15), if this thanksgiving be compared with others.
• quae [lēx] esse cum tēlō vetat (Mil. 11), the law which forbids [one] to go armed (be with a weapon).
• sī sēcum suōs ēdūxerit (Cat. 1.30), if he leads out with him his associates. [For sēcum, see § 144. b. N.1.]

a. The ablative is used without cum in some military phrases, and here and there by early writers:—

• subsequēbātur omnibus cōpiīs (B. G. 2.19), he followed close with all his forces. [But also cum omnibus cōpiīs, id. 1.26.]
• hōc praesidiō profectus est (Verr. 2.1.86), with this force he set out.

• mixta dolōre voluptās (B. Al. 56), pleasure mingled with pain.
• cûius animum cum suō misceat (Lael. 81), whose soul he may mingle with his own.
• flētumque cruōrī miscuit (Ov. M. 4.140), and mingled tears with blood.
• Caesar eās cohortīs cum exercitū suō coniūnxit (B. C. 1.18), Cæsar united those cohorts with his own army.
• āēr coniūnctus terrīs (Lucr. 5.562), air united with earth.
• hūmānō capitī cervīcem equīnam iungere (Hor. A. P. 1), to join to a human head a horse's neck.

b. Words of Contention and the like require cum:—

• armīs cum hoste certāre (Off. 3.87), to fight with the enemy in arms.
• libenter haec cum Q. Catulō disputārem (Manil. 66), I should gladly discuss these matters with Quintus Catulus.

Ablative of Degree of Difference