On five levels above diety the ai gets free unit upgrades , war happyness , almost no upkeep , mining , AGRICULTURE, THE WHEEL , HUNTING , and ARCHERY as free techs , a giant worker rate increase (I think like %225...) , free money from inflation , nine starting defence units , 7 workers , 3 scouts , big animal and barb bonuses. If that wasnt enough your Maintenance is greatly increased. Your tech costs are %55 higher than noble , you start out with 2 unheathy faces and zero happy faces (your palace still gives you one face though). If I remember correctly you pay Maintenance on your capital too. Also barbs start attacking ONE turn after the start of the game.