Cicero to Publius Caesius, written at Rome at an uncertain date — Perseus’s tradition (loco et anno incerto) groups it with the recommendation letters and provisionally before 56 BC. The letter is addressed to a man otherwise unattested in the corpus; the chief subject, Publius Messienus, is also obscure. The shape, however, is the standard commendatio: an inherited friendship between the writers’ fathers as the warrant, the request that the addressee take Messienus in fidem suam, the closing formula that Caesius will both gain a worthy man and oblige Cicero by doing so.