Century of Blood
From A Wiki of Ice and Fire
The Century of Blood or the Bleeding Years was a period of chaos that lasted for approximately one century after the Doom of Valyria. The colonies and conquests of the Valyrian Freehold broke away and bedlam erupted. The nine Free Cities were formed, only to fall into warfare against one another. On Dragonstone the Targaryens chose not to intervene, hoarding their own strength instead.