The classic story, once more. This is one of the latest interpretations (in which the EVIL ONE takes up the role of the tempter):
The messenger who carries it (the letter) is asleep under a tree, filled with ale generously provided by the fine young gentleman he met on the road... The rest is known: the royals break up, seek each other, and make amends.
"Filled with ale". This image surprises me. It's quite simple, in fact, it's as axiomatic as "The Pope is Catholic". The intoxicated person, the clichéd royal messenger, here does not conceal the fatal ethanol beneath his clothes (whether his belt, doublet, or waistcoat)... he becomes the container. For a while, he is fused with the liquid catalyst that has entered his blood. The distinction is not fuzzy, it has been completely blurred out. "Filled with ale", as in "filled with passion/joy/love/whatever emotion": intoxication is also a state of emotion. It takes over from within, whisks reason away, leaves the star-crossed one who has chosen, of his/or her own free will, unable to perform impulse control as long as the internal coup d'état lasts.