The Rosalyns was founded by an all-star all-girl lineup, including Anja Stax/Diabolik from the Loons, Lety Beers from the Schitzophonics, Diana Death from Chinese Rocks, Birdy Bardot from the New Kinetics, and Amy Gore from the Gore Gore Girls. The group first convened in late May 2013 at the Casbah, to play at the 30th anniversary party for local underground rock 'zine Ugly Things.
Diana Death left the group in 2014, with new guitarist Lori Sokolowski (also of Gloomsday) joining that August. The following summer, Amy Gore flew in from Detroit to play two high profile shows with the Rosalyns, at Tiki Oasis on August 16 (supporting Chocolate Watchband at the Crowne Plaza Hotel) and Burger A Go Go on September 5 at the Orange County Observatory.