Bengt Petter Larsson added to his name Hippias. He may have done this because there was another person living in the same area with the same name. Or he decided he wanted that surname. Before 1901 anyone could tell the priest they wanted a new name and as long as it was not a noble name, that became your surname.
There was a Hippias who was a tyrant in Athens, in the 6th century BC and another Hippias was a contempory of Socrates in the 5th century BC.
His sons took the surname of Hippias as well as his second wife Ingrid Johansson.
