Passage 7.15.1
Ῥωμαῖοι δὲ παρά τε τῶν ἀνδρῶν διδαχθέντες οὓς ἐς τὴν Ἑλλάδα ἀπέστειλαν καὶ ἐκ τῶν γραμμάτων ἃ Μέτελλος ἐπέστελλεν, ἀδικεῖν Ἀχαιῶν κατέγνωσαν· καὶ ἦν γὰρ Μόμμιός σφισιν ὕπατος τότε ᾑρημένος, τοῦτον ναῦς τε καὶ στρατιὰν πεζὴν ἐκέλευον ἐπʼ Ἀχαιοὺς ἄγειν. Μέτελλος δὲ παραυτίκα ἐπέπυστο ὡς Μόμμιος καὶ ὁ σὺν αὐτῷ στρατὸς ἐπὶ Ἀχαιοὺς ἀφίκοιτο· καὶ ἐποιεῖτο σπουδήν, εἰ ἐπιθεὶς αὐτὸς πέρας τῷ πολέμῳ φανῇ πρὶν ἢ Μόμμιον ἐς τὴν Ἑλλάδα ἀφῖχθαι.
The Romans, having learned from the men whom they had dispatched to Greece and from the letters sent by Metellus, concluded that the Achaeans were acting unjustly. Therefore, as Mummius was at that time chosen consul, they instructed him to lead both a fleet and an infantry force against the Achaeans. Metellus soon learned that Mummius and his army were coming against the Achaeans; thus he hurried to bring the war quickly to a conclusion himself, hoping to end it before Mummius reached Greece.