My Great Grandfather, on my father's side, used to trade cloth, across the north west of Spain, and along the way had a fling with a young lady. Unbeknown to him, this produced a boy who was brought up and educated by his mother in the mountains.
Grandfather lands a bit of an heiress and proceeds to have 5 daughters and one son.
When they were all grown up, a young man turns up asking Great Grandfather to acknowledge him and give him his surname. Great Grandmother, very upright, nearly had a fit. After a lot of negotiations, Great Grandfather agreed. The 'natural' son ended up being a very well known writer, and two of his children government ministers.
The legitimate children, lived very ordinary low working class lives.
HOWEVER.... my father's family are extremely proud of the illegitimate relation as if their surname had anything to do with the success of the young man.
Families are FASCINATING...
Another day I will tell the story of a great great grandmother on my mother's side who had to live in a cave for several years because the villagers wanted to burn her for 'being' a witch... yes siree, this was real!