Which preposition to use with getae

against Occurrences 1%

It may not be amiss, however, to give them these instructions, that in case of another war, the Getae against the Gauls, or the Indians, perhaps, against the barbarians (for with regard to ourselves there is no danger, our enemies being all subdued), by applying these rules if they like them, they may know better how to write for the future.

Which preposition to use with  getae