The Arthurian elements of the Le Morte d'Arthur indicate that the author's purpose is to ...

persuade

report

inform

entertain

The author's purpose is to entertain.

Like with any work of fiction the author's sole purpose is to entertain the reader. Le Morte d'Arthur is a book about the legends of King Arthur and his knights of the round table. It is based on stories of King Arthur and a poem by Lord Alfred Tennyson. Even though the legend of Arthur is still to this day debated as to whether he ever existed or not, Le Morte d'Arthur is a work of fiction and therefore is meant to entertain.