Papal Nuncio
Pope Gregory XV (1621–23) sent him as nuncio to the court of the Kingdom of Naples. Urban VIII sent him to accompany his nephew, Francesco Barberini, whom he had accredited as nuncio, first in France and then in Spain, where Pamphilj had the first-hand opportunities to form an intense animosity towards the Barberini. In reward for his labors, Giovanni Battista was made apostolic nuncio at the court of Philip IV of Spain (1621–65). The position led to a lifelong association with the Spaniards which was of great use during the Papal Conclave of 1644.
Read more about this topic: Pope Innocent X