I’m sure you all know what i mean by “old timey boxing style” i.e. hands held low, fists palm up, standing vertically if not slightly leaning back, very flat footed. When was this style of boxing replaced with the style we send nowadays? who originated the modern style?
It’s just a guess, but I would say the switch from bare knuckle to padded gloves would be the big change. With padded gloves you can take a few hits and more effectively block an opponent while moving forward. Bare knuckle would need to be much more defensive, leaning back and using your legs to create space.
The hands were held low in some photos so you could see the boxer’s face. In a fight they’d tend to be up higher. I recall somewhere there was speculation that without gloves you’d want to pick off punches with the back of your hands so that was the common stance.