The (original) Rubicon is a small stream in northern Italy just south of the city of Ravenna. During the prime of the Roman Republic, roughly the last two centuries B.C., it served as a northern boundary protecting the heartland of Italy and the city of Rome from its own imperial armies. An ancient Roman law made it treason for any general to cross the Rubicon and enter Italy proper with a standing army. In 49 B.C., Julius Caesar, Rome’s most brilliant and successful general, stopped with his army at the Rubicon, contemplated what he was about to do, and then plunged south. The Republic exploded in civil war, Caesar became dictator and then in 44 B.C. was assassinated in the Roman Senate by politicians who saw themselves as ridding the Republic of a tyrant. However, Caesar’s death generated even more civil war, which ended in 27 B.C. when his grand nephew, Octavian, took the title Augustus Caesar, abolished the Republic and established a military dictatorship with himself as “emperor” for life. Thus ending the great Roman experiment with democracy. Ever since, the phrase “to cross the Rubicon” has been a metaphor for starting on a course of action from which there is no turning back. It refers to the taking of an irrevocable step.