During the second half of the 3rd century BC, the Illyrian-Macedonian Wars continued because of the desire for territorial expansion by the Macedonian kings against the Dardanians, particularly against Paeonia.
An old alliance (rather than competitiveness) had existed between these two Illyrian states, because every time the Paeonians won their independence, the Dardanians gained an open road into Macedonia.
In 229 BC, Longarus, profiting from the fact that the Ardiaean Kingdom under Teuta was dealing with campaigns in Epirus, invaded its northern borders.
While Doson was dealing with a war in Greece in 222 BC, he hastened back home within a few days when news came that Longarus had invaded and that his forces were looting his kingdom.
Doson found the Dardanians still in the country and forced them to do battle, which he won but it was reported that he so over-exerted himself in shouting encouragement to his troops that he burst a blood-vessel and fell fatally ill.[7] Longarus despised the youth of Philip V and constantly provoked him.
While Aeropus' military incursion was limited and satisfied with Lychnidus, in 208 BC, Longarus attacked upper Macedonia, occupying the region of Orestida, taking 20,000 prisoners, and reaching the plain of Argestes.