Which preposition to use with tetrarchs

of Occurrences 5%

After the battle of Philippi, Herod secured the favor of Antony by an enormous bribe, as he had that of Cassius on the death of Caesar, and was made one of the tetrarchs of the province.

at Occurrences 1%

And though they be poor in show, vile and base, yet like Telephus and Peleus in the poet, Ampullas jactant et sesquipedalia verba, "forget their swelling and gigantic words," their mouths are full of myriads, and tetrarchs at their tongues' end.

Which preposition to use with  tetrarchs