On 2 October the same year, his uncle, Maffeo Barberini, newly elected as Pope Urban VIII, made him a cardinal, state secretary and papal legate to Avignon when he was twenty six years old.
Dana 2. listopada iste godine, njegov ujak, Maffeo Barberini, nedavno izabran kao papa Urban VIII., postavio ga je za kardinala, državnog tajnika i papinskog legata u Avignonu kada mu je bilo dvadeset i šest godina.