Was Poseidon treated fairly

I believe that Poseidon was not treated fairly by history because he is the brother of the almighty Zeus. Zeus became the ruler of all the gods and Poseidon became the ruler of the seas and horses. Horses only matter to horse people not to everybody, Zeus has control of everything which means he has control over every god, which means he has control over everything including horses.

I think he's treated just fine. He has rule over the sea and that is pretty powerfful indeed.