When was Julius Caesar assassinated?

Julius Caesar was assassinated on March 15, 44 BC, an event famously known as the Ides of March. This date has significant historical importance as it marked the end of Caesar's dictatorship and the beginning of a series of civil wars that ultimately led to the rise of the Roman Empire. The assassination was orchestrated by a group of Roman senators who feared Caesar's growing power and the threat he posed to the Republic.

The other options refer to different historical events or time periods: April 21, 753 BC, is traditionally regarded as the founding date of Rome; August 24, 79 AD, marks the eruption of Mount Vesuvius; and 509 BC marks the traditional date of the establishment of the Roman Republic. Therefore, these dates are not related to Julius Caesar's assassination.