BoxRec

Did you read where Fitzsimmons got the crap beat out of him by
the leader of a Football team in New Zealand ,when he was just 11 and the Footballer was a full grown man ?
That incident was what got him interested in defending himself
( and he still had searched high and low for the individual for years afterwards once he became proficent in boxing)

Fitzsimmons, from a relatively young age, fought against heavyweights. He trained with and learned from, no less than Peter Jackson.

Gearing a career towards fighting larger opponents in a professional setting is something that wouldn’t at all be practiced now. There is no need to take a supermiddle and have them actively train to beat larger fighters.