The elder Korbels came from a small town near the Czech/German border where Jews were almost entirely assimilated into secular life, hardly practicing, and lacking any communal institutions, including a synagogue.
The Jews in the small town did not practice their religion extensively.
Michelangelo wanted the tomb surmounted by the Piet? , now in the cathedral museum , but the Florentines almost didn't get even his body they had to smuggle it out of Rome.