"Elsa Einstein (18 January 1876 – 20 December 1936) was the second wife and cousin of Albert Einstein. Their mothers were sisters, making them maternal first ...
cousins, and further, their fathers were first cousins, making them paternal second cousins. Elsa had the surname of Einstein at birth, lost it when she took the name of her first husband Max Löwenthal, and regained it in 1919 when she married her cousin Albert." - (en.wikipedia.org 14.02.2022)