Pro Caelio is a speech given on April 4, 56 BC, by the famed Roman orator Marcus Tullius Cicero in defense of Marcus Caelius Rufus, who had once been Cicero's student but more recently was a political rival. Cicero's reasons for defending Caelius are uncertain though various theories have been postulated. The Pro Caelio is regarded as one of the best examples of Roman oratory known, and has been so regarded throughout history. It is noteworthy as a prime example of Ciceronian oratorical technique. Caelius was charged with vis (political violence), one of the most serious crimes in Republican Rome. Caelius’ prosecutors, Lucius Sempronius Atratinus, Publius Clodius (though it has been suggested that this is Publius Clodius Pulcher, it was more likely a freedman or relative), and Lucius Herennius Balbus, charged him with the following: Inciting civil disturbances at Naples; assault on the Alexandrians at Puteoli; damage to the property of Palla (about which we know little to nothing); taking gold for the attempted murder of Dio of Alexandria, then attempted poisoning of Clodia; and the murder of Dio.Caelius spoke first in his own defense, and he asked M. Licinius Crassus to defend him during the trial. Cicero's speech was the last of the defense speeches. Magistrate Gnaeus Domitius presided over the trial.