A few times I have been alerted to the fact that the dative case can show possession.
When I was reading Iliad 1:161, I Thought; "Aha! I know why moi is dative, it is a prize to me, ie; my prize.
The footnote in Pharr however indicates that the dative is to show that the thing is done to its (moi) disadvantage or advantage.
Here is the line: kai\ dh/ moi ge/raj au)to\j a)fairh/sesqai a)peilei=j, ...