Tyrannicide, (Pronounced: Tuh · ra · nuh · side) is the killing or assassination of a tyrant or unjust ruler, purportedly for the common good. In the Classical period, tyrannicide had been legally permitted, and encouraged.

Throughout history, many leaders have died under the excuse of tyrannicide. Hipparchus, one of the last Greek leaders to use the title of "tyrant," was assassinated in 514 BC by Harmodius and Aristogeiton, the original tyrannicides.

Another example for tyrannicide was the assassination of Julius Caesar by Marcus Junius Brutus.

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