Rise of the Runelords
Very little knowledge remains about Thassilon. What is known, is that it was a vast empire ruled by powerful wizards. The sheer size of the monuments they left behind testifies to their power, and the unnatural way many of these monuments have resisted erosion and the march of time testifies to their skill at magic. Most sages place the height of the Thassilonian empire at 7,000 to 8,000 years ago, but some believe it collapsed no sooner than 10,000 years in the past.