During the late 1920s, a bitter gang rivalry arose in New York between
Joseph "the Boss" Masseria, the most powerful mobster in New York, and
Salvatore Maranzano, head of the Castellammarese Sicilian clan. Masseria had demanded more money from Reina, prompting Reina to consider switching allegiance to Maranzano. When Masseria heard about Reina's plans, Masseria had him murdered in February 1930. Reina's murder exacerbated the tensions between the two camps, helping launch the
Castellammarese War. To head Reina's gang, Masseria appointed one of his loyalists,
Joseph Pinzolo. Both Gagliano and Lucchese hated Pinzolo and resented Masseria appointing an outsider as gang leader. In September 1930, Pinzolo was shot and killed by unknown assailants. To replace Pinzolo, Masseria appointed Gagliano as head of the Reina gang. It is speculated that Gagliano and Lucchese formed a secret alliance with Maranzano at this time while still professing loyalty to Masseria. As the war continued, Masseria began suffering more defeats and key defections. On April 15, 1931, Masseria was assassinated at a
Coney Island restaurant by several of his men. These defectors, guided by
Charles "Lucky" Luciano, had made a deal with Maranzano guaranteeing their power if they switched sides. However, after Masseria's death, Maranzano started promoting himself as the "Boss of All Bosses" for all the Italian-American criminal gangs in the country. Feeling betrayed and threatened, Luciano arranged Maranzano's assassination a few months later in September 1931. During this period of instability, Gagliano remained in control of the Reina gang. ==Cosa Nostra families==