Passage 7.15.2
ἀγγέλους οὖν παρὰ τοὺς Ἀχαιοὺς ἀπέστελλεν, ἀφιέναι κελεύων σφᾶς συντελείας Λακεδαιμονίους καὶ πόλεις ἄλλας ὁπόσας εἴρητο ὑπὸ Ῥωμαίων, τῆς τε ἐκ τοῦ χρόνου τοῦ προτέρου σφίσιν ἀπειθείας οὐδεμίαν παρὰ Ῥωμαίων ὑπισχνεῖτο ὀργὴν γενήσεσθαι. ἅμα τε δὴ ταῦτα ἐπεκηρυκεύετο καὶ ἤλαυνεν ἐκ Μακεδονίας τὸν στρατόν, διὰ Θεσσαλίας τὴν πορείαν καὶ παρὰ τὸν Λαμιακὸν ποιούμενος κόλπον. Κριτόλαος δὲ καὶ Ἀχαιοὶ λόγον μὲν φέροντα ἐς σύμβασιν προσίεντο οὐδένα, Ἡράκλειαν δὲ προσεκάθηντο πολιορκοῦντες οὐ βουλομένους ἐς τὸ Ἀχαϊκὸν συντελεῖν.
Therefore he sent envoys to the Achaeans, ordering them to release from their confederacy Sparta and the other cities specified by the Romans, and promising that, despite their previous disobedience, they would incur no anger from the Romans. While making these proclamations, he simultaneously advanced his army from Macedonia through Thessaly, moving along the coast by the gulf of Lamia. Critolaus and the Achaeans, however, rejected all overtures toward reconciliation, and proceeded instead to besiege Heracleia, which refused to join the Achaean League.