House Casterly is said to be a major part of Game of Thrones Prequel. As the spinoff will be set 5,000 years before the original series, it is the time when this family is known in Westeros. As details about the show emerge, here is what we know so far about the Casterlys.
At the time of the Age of Heroes, noble houses started to form, including House Stark and House Casterly. Hence, the latter house will be introduced in the new series, as hinted by the leaks and spoilers.
George R.R. Martin himself even said Lannisters would not be seen in Game of Thrones Prequel right away. So as this family originated from the Casterlys, fans may get to meet them first.
According to ScreenRant, House Casterly was not in the original series because they had been long gone. However, their history was never explored in Game of Thrones, so it might be revealed in the prequel.
A Song of Ice and Fire novel series didn't tell much about the Casterlys, so they were also not mentioned in the series. But, there is some history written on the companion book, The World of Ice and Fire.
Here, Corlos, son of Caster, formed the House Casterly. He was a huntsman, who killed a lion who was preying the sheep in their village near Lannisport. He tracked it down and slew it together with its mate with a spear, but let the cubs live.
His move pleased the old gods; thus, he led them into a lion's cave full of gold. Corlos started mining the cave; he moved inside and fortified its entrance to defend it from thieves and enemies. From here, he became Lord Casterly.
With time, the cave developed into a house. "Though never kings, the Casterlys became the richest lords in all of Westeros and the greatest power in the Westerlands, and remained so for hundreds of years," Martin wrote about their history. "By then the Dawn Age had given way to the Age of Heroes."
House Casterly's sigil remains unknown until today. But as its history has a connection with the lion, it might be safe to assume their seal is also the king of beasts, which the Lannisters might have adopted, per Inverse.
A leaked set photo revealed a house sigil that looked like a lion, which might be from the Casterlys. Since the snap was taken during the production at Grotta del Turco in Gaeta, Italy, where the House Casterly is believed to be set, it might have a connection with the clan.
Naomi Watts was also seen here, wearing her character's costume, which is also believed to have a connection with the Casterlys. HBO may drop official details about Game of Thrones Prequel soon when its 2020 or 2021 release date is nearing.
