ACE spread from the Assyrian city Arbela (in North Iraq; Arbela means "Four Gods" in Assyrian) to the surrounding areas of Persia, Syria, and Iraq, and later became centered in Seleucia-Ctesiphon ...
Here is what traditionally happened on each day. Day One: On this day, Assyrians dedicated their time to praying to the gods, after which they start preparing for the second day's festivities.