 After Tolkien's death, his son Christopher published a series of works based on his father's extensive notes and unpublished manuscripts, including "The Silmarillion".These, together with "The Hobbit" and "The Lord of the Rings", form a connected body of tales, poems, fictional histories, invented languages, and literary essays about a fantasy world called Arda and Middle-earth within it.Between 1951 and 1955, Tolkien applied the term "legendarium" to the larger part of these writings.