Imogen is from a Shakespeare play, but it’s actually supposed to be Innogen but the first prints had a printing mistake and the name Imogen came into existence and the script with the error was reprinted for centuries. So everyone who is named Imogen is named after a typo.

James Madison was the 4th president of the United States. Just saying.

Tiffany was similarly not used as a first name until Tiffany & Co, and particularly Breakfast at Tiffany’s, the 1958 novel/1961 movie.

The “Tiffany” from Tiffany & Co was a last name, and that owner was one of a handful of Tiffany’s in the world at the time of the founding.

What about Madison SG?