Nonia Celsa

Nonia Celsa is the name given by the Historia Augusta to the wife of Roman Emperor Macrinus, who ruled briefly in 217–218. She was the mother of Diadumenian (born in 208).

The only evidence of her existence is a happy letter allegedly written by Macrinus to his wife after he became Emperor. The first line is as follows: "Opellius Macrinus to his wife Nonia Celsa. The good fortune to which we have attained, my dear wife, is incalculable."

The letter can be found in the biography of Diadumenian, part of a collection called Historia Augusta. Such "documents" are generally considered fabrications and the biographer(s) is also infamous for inventing people and names. Without further evidence even the existence of Nonia Celsa is highly dubious.

...
Wikipedia