What are the most valuable ancient Roman coins?

Dean Kinzer, numismatics expert, says the most valuable ancient Roman coin ever sold was a Brutus coin, minted in 42 BC. The face of the coin has Brutus’s image, and the reverse shows two daggers and the inscription "EID MAR" which means “Ides of March.” It’s basically a gangster coin saying, “I killed Caesar.” Only a few exist, and a gold one sold for $4 million. Another, with a hole from being worn as jewelry, sold for $2.5 million. Silver versions are more common but still six-figure coins.