What would Leonardo study after Year 12?

Just over five centuries ago, a young man wrote a job application to Ludovico Sforza, the Duke of Milan. The year was 1482, and the applicant was a 30-year-old man, recently arrived in Milan from the Florence of the Medicis. The draft of the application still survives. It is surely one of the more unusual CVs in history, and it should be, as the author was Leonardo da Vinci.