8 Adar (Purim)

Esther 3,1 says "(1)Gidal Hamelech Achashverosh Es Haman...(2Vayenaseahu, (3)Vayasem Es Kiso me'al kol Hasarim..." Why all 3 forms of saying Haman was promoted? What's each one adding? Also why do we refer to it as putting his chair.... We should say put him over all the officers, not his chair!