Before the Colt revolver only one and two-barrel flintlock pistols had been invented for hand held use. Colt revolvers were all based on cap-and-ball technology until the Smith and Wesson license on the bored-through cylinder (bought from Rollin White) expired around 1869.
According to www.midwestgunshows.com: "Horace Smith & Daniel Wesson formed their second partnership (S&W) in 1856 for the development and manufacture of a revolver chambered for a self contained metallic cartridge. During this development period, while researching existing patents, it was found that a Rollin White had patented a bored through cylinder for a paper cartridge some time earlier."
A licensing agreement was arranged between Smith and Wesson and Rollin White. In 1855, Rollin White patented the bored-through cylinder.
According to www.armchairgunshow.com: "The Rollin White patent covered the right to make a revolver cylinder bored-through end to end - an obvious requirement for an effective cartridge revolver. This fact didn't slow down some firms, who proceeded to make the highly popular cartridge style revolvers. Some used their own designs, and some just produced outright copies of the Smith and Wesson pattern. Smith and Wesson pursued redress in court, resulting in several US makers being required to mark "Made for S&W" or words to that effect on their revolvers."