Caligula, Life of a Roman Emperor

Suetonius' most important surviving work is known as the De Vita Caesarum, a
set of twelve biographies of the successive Roman rulers. The emperor Caligula
was one of the strangest and cruelest rulers that ever lived, and most of what
is known about his reign comes from Suetonius. The first six months of his
reign appear to have been moderate and successful; but after that, he fell
into a spiral of sadism, sexual perversity, and plain insanity that made him
one of the most hated tyrants of all time. His biography gathers many
extravagant anecdotes, from naming his horse consul to calling people to his
palace in the middle of the night just to play a strange game of fright with
them. He was eventually assassinated, but not before many strange omens
predicted the event, according to Suetonius.