general_fact: 1535 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 1535 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 1535 is an uninteresting number.
historical_date: March 14th is the day in 44 BC that Casca, Cicero and Cassius decided, in the night before the Assassination of Julius Caesar, that Mark Antony should stay alive.