Late June 43 BCE: To Decimus Brutus (at Eporedia) from Cicero (at Rome)
'Now it is not others that you must try to outdo, but yourself.'
From Marcus Cicero to Decimus Brutus, greetings.
Although I found your letter absolutely delightful, it was still more delightful that while you were so thoroughly occupied, you instructed your colleague Plancus to write and make your excuses to me—he did this very well. But I find nothing more loving than your dutifulness and care.
The Senate and People of Rome are very grateful for the alliance you formed with your colleague and the agreement between you, which was disclosed in a joint letter.1 As for the rest, carry on, my Brutus—now it is not others that you must try to outdo, but yourself.
I shouldn’t write anything more, most of all to you, whom I consider an instructor in brevity. I eagerly await a letter from you, and especially the sort of letter that I most wish for.2
Goodbye.
Latin text of ad Familiares 11.15 | Glossary | Historia Civilis video overview of 44-43 BCE
i.e. one announcing victory or the end of the war.