Fait général: 1356 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 1356 is a truncated square pyramid number.
Culture générale: 1356 is a boring number.
Date historique: September 17th is the day in 456 that Remistus, Roman general (magister militum), is besieged with a Gothic force at Ravenna and later executed in the Palace in Classis, outside the city.