The naming of bastard children

Sorendenese men who have children out of wedlock can give their name to these offspring without bringing them into their proper family.
This is indicated using 'de' in the person's name. For example, 'Basil de Brush' would be the recognised bastard son of someone from the Brush family.
As there are many famous families who have this signifier as part of their name, there is little stigma associated with it.