Complex sentence: Paramount cast her in "War and Peace" (1956) which was shot in Rome alongside Mel Ferrer and Audrey Hepburn before RKO gave the actress her first leading role in "Back from Eternity" (also 1956).
Split into simpler sentences: Paramount cast her in "War and Peace" (1956) which was shot in Rome alongside Mel Ferrer and Audrey Hepburn. Meanwhile, RKO gave the actress her first leading role in "Back from Eternity" (also 1956).