Colloquo Votar

Colloquo Votar is an unseen character in Game of Thrones. He is the author of the Jade Compendium, a book considered a major source of legends from Qarth, Yi Ti, and other lands around the Jade Sea.

Season 7
Colloquo Votar and his Jade Compendium are mentioned on a page that Gilly is seen reading in another history book, The World of Ice and Fire.

In the books
In the A Song of Ice and Fire novels, Colloquo Votar is stated to have been an adventurer from Volantis. He is apparently long dead by the time of the main novels, though exactly when he lived is unclear.