Footnotes:

1. a random stillborn child with the upper half of a human and the lower half of an animal was presented to him in his bedroom (first off, why??). Apparently the human half represented Alexander and the monster half represented the regression of his empire. This omen is from the original Alexander Romance.
2. ravens falling down dead at his feet. The ancient Greeks, at least in myth, took bird-related events seriously. This one is from Plutarch (all of the Plutarch omens are in Paragraphs 73 to 74 in Part 7)
   
3. Alexander's diadem coming loose and falling into the river. This omen is considered historical, though it also appears in the Romances. There's a longish story attached to it, but basically: after losing the diadem, some guy (the person always changes in every story) would jump into the river and help pick it up, and commit the faux pas of tying the diadem around his forehead. Another related omen is of a tranced man accidentally sitting on Alexander's throne. Unfortunately that story doesn't work as an out-of-context single panel so it's not featured here.
4. A donkey defeating and killing a lion. Alexander's star sign is Leo and he's attached to the lion in the Romance. This one also comes from Plutarch.
5. A historical omen: Alexander's Indian ascetic friend had committed self-immolation at his own funeral pyre. Before he went, he had told Alexander he would "see you soon, in Babylon".