The World of Ice and Fire (sourcebook, 2014)700 BCabout a thousand years ago250 yearsA Song of Ice and Fireabout 5,000 years agoA Dance with Dragons (book, 2011)House of the Dragon Season 1
Other
Cause of death
annihilation of their society by Valyrians—Defeat by Valyrian dragonlords—Greyscale—None mentioned