In 18th century, boxing was more different than what we have today.

Bare-knuckle boxing
Also known as fisticuffs or prizefighting

The creator of this martial art is unknown, but we do know it came from Ireland.
The parenthood of this are Ancient Greek boxing and Street fighting.

The first champion of bare-knuckles was James Figg, an English boxer, and held his title from 1719 to 1730 which is 11 years.

The longest bare-knuckle fight was 6 hours and 15 minutes between James Kelly and John Smith when Smith finally gave in after 17 rounds. This all took place in Australia,Victoria, near Fiery Creek on December 3rd, 1855.

The longest professional career is listed to be Jem Mace, who fought more than 35 years while in his 60s, his last exhibition was around 1909 at the age 79.

While the techniques of bare-knuckles have been said to be about striking, historically it also included throws, arm locks, choking, and surprisingly even kicks, however these were banned during the several rule changes which turned classic pugilism into what kind of boxing we have today. Although some of these techniques are stilled used sometimes in the modern era.