Legendarium

Legendarium is the term Tolkien used for his mythology of Eä.

The Letters of J.R.R. Tolkien

Letter 131: "This legendarium ends with a vision of the end of the world..."

Letter 153: "...my legendarium, especially the 'Downfall of Númenor' which lies immediately behind The Lord of the Rings, is based on my view..."

Letter 154: "Actually in the imagination of this story we are now living on a physically round Earth. But the whole 'legendarium' contains a transition from a flat world..."