In To Kill a Mockingbird why did Harper Lee choose Arthur as a name for one of the characters? What is the origin?

In To Kill A Mockingbird, Boo Radley's given name is Arthur. The name Arthur has a Roman origin from the Artorius clan. Arthur means noble or courageous. It is very interesting that Lee chose this particular character to have the name Arthur because Boo Radley is the town recluse and does not seem courageous at all. He always stays in his home, seemingly fearful of the world outside. Jem and Scout are fascinated by the myths that depict Boo as a monster and often try to catch sight of him. When the children are attacked by Bob Ewell, it is Boo Radley who saves them and kills Ewell. It is in this moment that he seems to truly live up to his name and shows tremendous courage.