These sections were written by Martin on his own however, he wrote much more than at first intended, and in the end delivered 180,000 words on Targaryen history. The World of Ice & Fire, written from the perspective of Maester Yandel, contains sections from the perspective of Archmaester Gyldayn.
Much material published in Fire & Blood originates from the writing of Martin's 2014 book The World of Ice & Fire.
