So exactly who was Prince Rainier related to? I do know he married actress Grace Kelly and her father was Judge John B Kelly of Philadelphia.
He and his wife were close friends with the Murphy family from Asylum PA who ran LaSalle University in the 1930's.
On the wall in the main area of the University, the name Hon John B Kelly sits with a few other well known Catholic names. At first, the University claimed that was Princes Grace Kelly's father. Later they said they were mistaken as there where many Catholic Judge John B Kellys in the Philadelphia area in the 1930's.
Then they decided to seal all the operation records of the Murphy family on the Murphy family running LaSalle University in the 1930's.