An anachronism is an error of chronology in a literary work, meaning something that is out of time or place in the setting. William Shakespeare's play "Julius Caesar" has multiple anachronisms. The most prominent example is a mechanical clock. The mention of a doublet is another anachronism.
In the second act of the play, Brutus and Cassius are plotting Julius Caesar's assassination, and the clock strikes three during their discussion. The play "Julius Caesar" is set in 44 A.D., before mechanical clocks were invented, though they were used in Shakespeare's time. During the Roman era, people used sundials to tell the time, which do not make a noise. Scholars have argued that this anachronism is not a mistake but instead is a device used to underline the extent of Julius Caesar's power. In Shakespeare's time, people tracked the passage of time with the Julian calendar, created by Julius Caesar. By devising his own calendar, he was interfering with time, which was seen as a sign that he was too powerful for the good of the nation. However, this is just one interpretation of the clock in "Julius Caesar."
A doublet, a close-fitting jacket, was a fashion wore by men during Shakespeare's time but was not worn by Romans at the time the play is set.