I have noticed that almost every well known boxer prior to 1920 or so fought orthodox. I’m sure there had to be some decent southpaws out there…who were they?
Lew Tendler, off the top of my head, did fight in the teens and scored some good wins in that period too. He was basically retired by the mid '20s. There is film of him against Leonard. I believe Al McCoy and Johnny Wilson were also southpaws. Google says William “Abednego” Thompson was a southpaw who won the British Title in 1839 (for reference, British Title was one the titles back then, very prominent).
Other world champs who started their pro career before 1920, include Tiger Flowers, Young Corbett III and Pete Latzo.
Batoro Kachapati didn't get but a few fights in the west but we would have to include him. Oh, hey, Bukkake. Nice to see you posting again, bruh.
Oldest lefty I've found was Tom Tyne. He won the lightweight championship, defended it against a young Daniel Mendoza then vacated to win the Welterweight title. Which he then lost to Mendoza. 1770-1780s IIRC. I found no mention of anybody earlier as being left handed. Trust me. I looked.
I believe the earliest Southpaw Heavyweight Belt Holder (England) was in 1832: William 'Bendigo' Thompson.
Thanks for all the replies. Just one last question…does anyone know if left-handed fighters in those days were generally encouraged to still fight in the orthodox stance?