Now, even before this there had been differences between him and Pyrrhus, and Pyrrhus had overrun Thessaly;
Edition :
Plutarch Lives IX: Demetrius and Antony, Pyrrhus and Caius Marius, Ed. Jeffrey Henderson, trans. Bernadotte Perrin (The Loeb Classical Library 101), Harvard University Press: Cambridge/MA - London 1968 (first ed. 1920).
Remark :
titel: καταδρομαὶ probably refers rather to plundering than to an actual occupation of Thessaly by Pyrrhus. date: Pyrrhus invaded Boeotia in 292/91 and Macedonia in 289/88, so he must have come to Thessaly in between these years. See https://referenceworks.brillonline.com/entries/brill-s-new-pauly/pyrrhus-e1015710?s.num=0&s.f.s2_parent=s.f.book.brill-s-new-pauly&s.q=pyrrhus#e1015740 long-term consequence: Demetrius attacks Pyrrhus as a reaction to this. This is mentioned in the rest of the paragraph and 7.3.