Dragon Skeleton Chalice
Skulls of the Targaryen Dragons History:
After the fall of House Targaryen, King Robert I Baratheon replaced the dragon skulls with banners and tapestries. The skulls were stored in a dank cellar in the Red Keep where they remain.
There are nineteen skulls of various sizes. Some of the skulls have been identified but the identity of most of the dragon skulls are unknown. It is possible that some of the dragon skulls may have been brought to Westeros by the Targaryens when they fled Valyria prior to the Doom. George R. R. Martin has said that there were once dragons all over, so it is possible some skulls could have originated from Westeros. Read more at: https://awoiaf.westeros.org/index.php/Skulls_of_the_Targaryen_dragons