Final answer:
Alfonzo of Naples died during a plague epidemic in 1361.
Step-by-step explanation:
Alfonzo of Naples died during a plague epidemic in the year 1361 when he was 25 years old. The exact details of his death are not mentioned in the provided information, but it is stated that he died in Milan during the devastating plague that had invaded the city. The plague, which was also known as the Black Death, was a highly contagious disease caused by the bacterium Yersinia pestis. It spread through fleas that lived on rats and was transmitted to humans through flea bites.