Laudator Temporis Acti

Cicero, Letters to His Friends 4.9.3 (tr. W. Glynn Williams):

All is misery in civil wars; our ancestors never even once had that experience; our generation has already had it several times; but nothing is more miserable than victory itself; for though it falls to the better men, it nevertheless makes those very men more arrogant and less self-controlled, so that even if they are not so by nature, they are compelled to be so by necessity. For there are many things a victor is obliged to do even against his will at the caprice of those who helped him to victory.

omnia sunt misera in bellis civilibus, quae maiores nostri ne semel quidem, nostra aetas saepe iam sensit; sed miserius nihil, quam ipsa victoria, quae etiamsi ad meliores venit, tamen eos ipsos ferociores impotentioresque reddit; ut, etiamsi natura tales non sint, necessitate esse cogantur. multa enim victori eorum arbitrio, per quos vicit, etiam invito, facienda sunt.