The flyweight division (112 lbs.) was established in 1910, first in England and then in the United States. The history of the flyweight championship in the ensuing two decades is complex, to say the least, but interesting. The first American flyweight was Frankie Mason. Jimmy Wilde, of England, knocked out Johnny Rosner in Liverpool on April 24, 1916 to gain the world championship.

On February 11, 1921, Johnny Buff (real name John Lesky) took the American title from Frankie Mason in a 15 round decision in New Orleans. Pancho Villa (real name Francisco Guilledo), of the Philippines, then took it away from Buff in an 11th round knockout in New York on September 14, 1922. On March 1, 1923 Frankie Genaro outpointed Villa in 15 rounds in New York to become the American champion.

On June 18, 1923, world champion Jimmy Wilde came to the United States and elected to fight Villa instead of American champion Genaro. Villa knocked out Wilde in 7 rounds, and became known as world champion, although Genaro still held the American championship. Villa died in San Francisco on July 14, 1925.

On August 22, 1925, Fidel La Barba outpointed Frankie Genaro in a 10 round bout in San Francisco, to capture the world flyweight championship.

When La Barba retired in 1927 to attend Stanford University, the championship went into turmoil. With no recognized champion to succeed La Barba, Corporal Izzy Schwartz for a while was rated as champion by the New York Boxing Commission by virtue of his defeat of Newsboy Brown by a close decision in New York on December 16, 1927. But his title was not recognized outside of New York. In the meantime, Newsboy Brown defeated Johnny McCoy in Los Angeles to gain the California flyweight championship in January of 1928.

In order to crown an its champion, the New York Commission ordered an elimination tournament, beginning in November of 1929. The tournament culminated in a 15 round match between Midget Wolgast and Black Bill, of Cuba, at Madison Square Garden on March 21, 1930. Wolgast, of Philadelphia, outpointed Black Bill to become acknowledged by the New York Commission as world flyweight champion.

At about the same time, New Jersey elected Willie La Morte as champion, and the National Boxing Association, representing nearly 30 states, elected Frankie Genaro. Wolgast was scheduled to meet Genaro in New York in May of 1930, but the match was called off. Instead, Wolgast fought La Morte and scored a TKO against him in New York on May 16, 1930. Genaro also defeated La Morte in a 10 round decision in New York on August 6, 1930.

On December 26, 1930, Genaro met Wolgast for what would have determined the undisputed flyweight champion of the world. But the 15 round fight ended in a draw.

The following year, Genaro was knocked out in the 2nd round by Young Perez, a French boxer, in Paris on October 26, 1931. Perez was then recognized as flyweight champion in France, but the National Boxing Association elected Jackie Brown of England in 1933, and the New York Commission elected Midget Wolgast in 1934. In 1935, the New York State Athletic Commission rated Small Montana as its champion, and the NBA did not nominate anyone.

On September 16, 1935, Benny Lynch knocked out Jackie Brown in the 2nd round in Manchester, England to claim the world's title. The next week, Small Montana outpointed Midget Wolgast in 10 rounds in Oakland, California to also claim the title. Then, on January 9, 1937, Lynch met Montana in England to determine the undisputed championship. They fought 15 rounds, after which Lynch, on points, was declared the undisputed flyweight champion of the world. He held that title until he resigned on June 19, 1938.

It was an exciting era. Flyweight boxing has not quite been the same since.