Poggio was appointed
Bishop of Tropea on 4 October 1541. He appointed a
Vicar General to administer the diocese, since he was again nuncio to Spain from September 1541 to December 1551. From the 1540s until 1551 Poggi was papal
nuncio at the Spanish court of the
Charles V, Holy Roman Emperor. In 1554,
Pope Julius III dispatched him to attempt to convince
Francis Borgia, a ranking Spanish nobleman who had recently renounced his position to enter the
Society of Jesus, to accept a cardinal's hat, but Borgia refused. In November 1548 Prince
Philip of Spain, son of King
Charles V of Spain, made a triumphal entry into
Genoa en route from Spain to the
Spanish Netherlands. As nuncio, Poggio was among the dignitaries who accompanied him. As was normal at the time, Poggio accepted loans from the Olivieri banking house, leading financiers of the city. Given his important positions as nuncio to Spain and general treasurer, the amounts lent to him were unusually large. ==Cardinal==