Prince Giovanni Battista Rospigliosi (1646-1722), first duke of Zagarolo, nephew of Clement IX, married Maria Camilla Pallavicini (1645-1710), niece of cardinal Lazzaro Pallavicini, in 1670, bringing together, thus, a great heritage. In 1708 they bought the "Palazzo del Giardino" at the Quirinale from the Barberinis, where they introduced their entire conspicuous art collection.