Caligulism does not appear in the World Book Dictionary. The closest words are caliga, a Roman military footwear, caliginosity and caliginous, relating to a dark mistiness or murky quality. Caligula, which means 'Little Boots,' was a Roman Emporer, 37-41. He supposedly had a very dark personality which was kept in private until after he suffered an illness at the age of 38, then his foul excesses were quite public.