When my father was born, his parents gave him a normal given name, but endowed his middle initial as only a single letter. They said, when he grew up he could choose whatever name fit that initial.

The initial happened to match his father's given name, and when he was old enough, he reliably chose to take that name as his middle name. It is certainly an endearing story of filial devotion, and a distinct lack of finicky SQL databases or web input validation in the 1950s.