Interesting book

https://www.amazon.com/When-Boxing-Was-Jewish-Sport/dp/027595353X

Among the first Champions would be Dutch Sam.
Samuel Elias, better known as the Dutch Sam, was a professional boxing pioneer, active between 1801 and 1814. Known as the hardest hitter of his time, he earned the nickname "The Man with the Iron Hand". He was also known as "The Terrible Jew", referring to his Jewish heritage.