You might be saying, wait, I thought Alexander was a lawful successor. Alexander's probably thinking the same thing. This so irritated Alexander, that throwing one of the cups at his head, throwing it at Attalus' head, you villain, he said, what, am I then a bastard? Then Philip, Alexander's dad, taking Attalus' part, so he didn't take his son's side, he'd take the side of his in-laws, rose up and would have run his son through, but by good fortune for them both, either his over-hasty rage or the wine he had drunk made his foot slip so that he fell down on the floor, at which Alexander reproachfully insulted over him. See there, said he, the man who makes preparations to pass out of Europe into Asia, overturned in passing from one seat to another. So if this account by Plutarch is even vaguely true, it shows this real tension that is forming between Alexander and his father. And it's, of course, being goaded on, or likely to be goaded on, by his mother Olympias, who was the primary wife for a little bit, but now she's being pushed aside in favor of this Macedonian Cleopatra.