Barberini and his younger brother Maffeo played a role in reconciling the Barberini family with the papacy (at that stage Pope Innocent X) after the Wars of Castro. Maffeo married a niece of Pope Innocent X and Carlo was elevated to cardinal by Pope Innocent X in 1653. It had originally been proposed that Carlo marry the Pope's niece but he instead suggested it was an ecclesiastic career that he sought.