After this, he actually made peace with Demetrius, but in a little while, when Demetrius had set out for Asia, he once more took the advice of Lysimachus and tried to bring Thessaly to revolt, besides waging war upon the garrisons of Demetrius in the Greek cities. For he found that the Macedonians were better disposed when they were on a campaign than when they were unoccupied, and he himself was by nature entirely averse to keeping quiet.
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 :
motive: Since Pyrrhus wants to keep his army from mutiny, he acted for social as well as political reasons. date: This must have taken place after 288, when Pyrrhus conquered Macedonia, and before 284BC, when he was again driven out of the country.