Final answer:
The information provided does not specify how long after being attacked Alfonso of Naples died. The context mainly discusses the broader impact of the plague and military conflicts during the Renaissance period without detailed correlation to Alfonso's death.
Step-by-step explanation:
The exact date of the death of Alfonso of Naples after he was attacked is not provided in the given information. However, the text indicates that Florence was threatened by the King of Naples between 1408 and 1414, who then died before he could conquer Florence. According to the given information, this King of Naples could potentially be Alfonso I, who lived during that period. However, there's no clear historical evidence in the provided text that links his death to an attack or specifies how long after being attacked he died.
The details given mostly revolve around the impact of plague and military conflicts on various individuals and regions, showcasing how diseases like the plague affected numerous lives, including Francesco Petrarch's friends and loved one's tragedy that shaped the historical narrative of that time. In such tumultuous periods, loss and warfare were frequent, and Florence attributing its survival to divine favor is a testament to the era's belief systems and the constant shadow of death over Renaissance Italy.