The Rosato Brothers, Carmine and Tony, were two gangsters who worked for Giuseppe Mariposa in the 1930s, before falling under the aegis of Peter Clemenza. They were backed up by Hyman Roth in Miami during the 1950s to make a power-play within the Corleone family.
It was believed that the Rosatos had somehow caused the death of Clemenza, having been promised three territories in The Bronx before he died. Clemenza's successor, Frank Pentangeli, refused to hand over the territories, but was told to negotiate by Michael Corleone, who was in business talks with Roth, who supported the Rosato brothers. At a peace meeting, Pentangeli was nearly assasinated by the Rosatos.
Roth conspired with the Rosato Brothers to place the blame for the failed hit on Michael Corleone, making Pentangelli feeling betrayed by his Don and causing him to co-operate with the law, thereby further tearing apart the Corleone family from within.
Real life sourcesEdit
The Rosato Brothers are primarily based on the Gallo Brothers Albert "Kid blast" Gallo and Joey "Crazy" Gallo. The assassination attempt on Pentangeli is inspired by a similar incident in which Larry Gallo was strangled during a sitdown and narrowly escaped with his life due to the intervention of a policeman.
As a side note, the c-note discussion between Pentangelli and Carmine was also quoted directly from the conversation at the door that Larry Gallo had before the attempt on his life.