In 688 BC, it became an Olympic event and in 616 BC, it was extended to boys. Instead of gloves, ancient boxers wrapped leather thongs (himantes) around their hands and wrists which left their fingers free.
Ancient boxing had fewer rules than the modern sport. Boxers fought without rounds until one man was knocked out, or admitted he had been beaten. Unlike the modern sport, there was no rule against hitting an opponent when he was down.
Fun Fact: Boxing was added in the 23rd Olympiad.
The definition of the event was two men fighting until one admits defeat or until one person is knocked out. They did not fight in a ring it was just an open area.
Ancient Boxing is similar to today's boxing since one of the fighters can be knocked out.