According to "The Epic that Never Was", Director Josef von Sternberg
asked the Costume Designer John Armstrong
to prepare a briefing on the Vestal Virgins for him. Armstrong reported the factual details on the Virgins, that there were about six of them and that they dressed modestly. Von Sternberg told him that would not do for his picture, and instructed him to prepare sixty extras to be Vestal Virgins, in what appear to be bikinis, and Armstrong also provided each a semi-transparent circular veil to cover themselves. The resulting scene is quite striking and beautiful and fits in well with the film's intended "epic" proportions. But it is historically inaccurate, by order of the director. See more
Caligula was murdered. He ruled by force, but a state such as I hope to establish cannot condone murder. For violence is an enemy to justice. And in the name of justice, I call upon the murderers of Caligula to step forward.
Capt. of Caligula's Guard
We killed a tyrant, Caesar.
But you broke your solemn oaths as Roman soldiers, to protect your Emperor. You didn't strike for your country. You killed in the name of your own private grudges. I was with you Cassius, when the tyrant kicked you, but you were not content with ...