"Caesar's assassination [on the Ides of March] was a central event in marking the transition from the Roman Republic to the Roman Empire." ~ThoughtCo
His assassination on March 15th started a series of bloody civil wars that led to the end of the Roman Republic, and the formation of the Roman Empire.
Chancellor Palpatine: "The republic will be reorganized into the first Galactic Empire... (applause) ...for a safe and secure society!"
Senator Amidala: "So this is how liberty dies? With thunderous applause."