No pun intended - this is the third Caligula movie I have seen. All are about excesses ... about mad men in power of sorts. And have obviously the main character in common - although this revolves around a few more people than just him - the title already suggests that, so no brownie points for seeing through this (or any pieces of clothes that will allow that too).
Acting is all over the place, but I was only able to watch the English dubbed version. Not that what they filmed was one language - back then they used to film movies in many different languages in Italy that is. Anyhow the emotions are a bit lost - even those in the quite explicit scenes. But you probably will not watch it because of that. Many versions exist of the movie - and the movie is a quite the mess ... makes almost no sense, but tries to shock you.
Does not succeed in the way the other two movies were able to. This apparently builds upon other movies (there is one where Messaline is the main character), which I have not seen ... I doubt this would have fared better in my mind if I had though .. just saying.