His brilliance and literary skills made the young humanist much in demand. When he left Rome he was engaged in service to Cardinal Ercole Gonzaga as tutor to the sons of his brother Ferrante Gonzaga, Francesco Gonzaga and Gian Vincenzo Gonzaga, both future cardinals. He moved with them to the literary capital of Italy, the city of Ferrara ruled by the House of Este. Possevino was connected with the Aristotelian revival associated with Francis Robortello and Vincenzo Maggi (1498–1564) that generated many treatises on literary and courtly matters including his brother's "Dialogo dell'honore" and his early works. When the University closed in Ferrara due to the Italian War of 1551–1559, Antonio moved to Padua. At this time Don Ferrante, his wards' father, died in the aftermath of the Battle of St. Quentin (1557). Possevino had become an expert in the historical training of princes and was writing commentaries on this battle exalting the victory of Emanuele Filiberto, Duke of Savoy. This produced a Piedmontese commendature that he had to renounce in order to become a Jesuit, a severe hardship for his family, as his brother Giorgio was in jail and he was supporting his nephews, Giovanni Battista Bernardino Possevino and Antonio Possevino, both future translators and authors.