Born in 12 AD, the son of the great general Germanicus, the little blond poppet Gaius was the darling of the legions - who gave him the nickname Caligula or "little boot". There was widespread rejoicing in Rome when, in 37 AD, Caligula succeeded his unpopular uncle, the Emperor Tiberius. Then things started to go wrong as one by one, Caligula pioneered the most popular themes of <a certain image board>.
Wincest! (With all three of his sisters.)
Furry thread : Consulting with Senator (& lover?!) Incitatus
It's a trap! (Rate me /b/)
You laff, you lose - God mode.
His behavior grew increasingly erratic: on one occasion, when presiding at the Games, he grew bored and had an entire section of the crowd thrown to the lions during the intermission. Then, in 40 AD, Caligula declared himself a god - somewhat limiting the scope of atheism threads.
One of the Emperor's ceremonial roles was to set the daily watchword for the Praetorian guards stationed in and around Rome. With hindsight, this wasn't a suitable job for a /b/tard. The army took offense at being obliged to greet each other with words like "cock", "whore" and "big boy" and, in 41 AD, they killed Caligula, his wife and daughter.
The above pictures are from the brilliant BBC dramatization of Robert Graves' books I,Claudius and Claudius the God - probably the greatest miniseries ever made. A word of warning though, the series was made in 1976 and may be a little stagey for modern tastes. (You might prefer Rome or Spartacus.)
Finally, if you're at all interested in reading history, you'll enjoy The Twelve Caesars by Suetonius. It's a chatty, gossipy biography of the first twelve Roman emperors, written by a palace insider around 119 AD.