Mike "Twin" Sullivan was born in
Cambridge,
Massachusetts, on September 23, 1878, and resided in neighboring Boston for much of his career. He had a twin brother Jack, the origin of his nickname, "twin", and was the youngest in an Irish family of several siblings. His twin Jack was an accomplished middleweight boxer as well, once claiming the Middleweight Championship of the World when he defeated
Tommy Burns on March 7, 1905. Jack fought top talent as did Mike, and they shared a few of the same opponents. His brother Dan was a less well known boxer. Sullivan had three historic bouts with Hall of Famer and reigning lightweight champion
Joe Gans, in September 1905 and January and March 1906 with the first in
Maryland and the last two in
San Francisco and
Los Angeles. Significantly, Sullivan lost the last two bouts to the lightweight champion by knockout and technical knockout, though their first bout was a close draw. In the San Francisco fight, Sullivan's first sanctioned Welterweight World Title match according to
BoxRec, Gans won by knockout in the fifteenth of twenty rounds. In an important note, the
Rock Island Argus wrote of the San Francisco fight, "Gans showed wonderful form and was easily the master of his white antagonist at all times." It did allow that the first three rounds were fairly even fighting. After his fights with Gans, Sullivan met Rube Smith, an accomplished welterweight contender three times in April, July, and August 1906 in Colorado, winning in an eighteenth round knockout in April, but drawing in the other two matches. Sullivan lost to future welterweight
Harry Lewis on February 21, 1907, in a ten-round points decision in Denver. Lewis would use this victory and his subsequent knockout of
Honey Mellody one year later on April 20, 1908, to establish what most boxing historians consider a legitimate claim to the World Welterweight Title. Many boxing sanctioning organization today simply fail to list World Welterweight champions prior to 1910 or 1915, as most of these organizations did not exist during that period, and there was less widespread recognition of world champions. ==Winning the Welterweight World Title==