The "AX" after the year refers to "after Xenens". The Xenens were a technologically advanced civilization that pretty much dominated the world until the Elitions (sorcerers) expelled them through an inter-world portal.
Chapter 1 of Enchanted has a date of 526AX June 2. That means it takes place 526 years after the expulsion of the Xenens. For simplicity's sake, I kept our world's months.
The reason I included dates is because the series tells a very big story with events in the past heavily influencing the present. These past stories are told in the .5 books. Also, some of the novels overlap in time. Wilderness (Book 2) and Machination (Book 3) cover much of the same timeframe.