Alfonso's education was at his father's humanist court. His tutor between 1468 and 1475 was the humanist Giovanni Pontano, whose "De principe" describes the proper virtues and manner of life becoming to a prince; the work took the form of letter of advice to the twenty-year old Alfonso, then Duke of Calabria, in 1468. Pontano dedicated a further treatise on courage, "De fortitudine", to Alfonso in 1481, after his victory over the Ottoman invasion of Otranto, and remained close as his personal secretary until Alfonso's abdication.