Märta Allertz.

About Märta Allertz

Märta Allertz often wrongly referred to as Brita Allerts, was the royal mistress of Charles X Gustav of Sweden. She was the mother of the illegitimate son of Charles X, Gustaf Carlson, who later became a count and a high-ranking military official. The year of her death is unknown: she is last confirmed alive in 1665, and was surely dead by 1677, when her death estate was listed.