I don’t claim any originality in this comparison, I am sure something like it can be found in the vast corpus of Shakespeare commentary, but I think there will be something specific about my way o expressing it.
In Shakespeare, we have two plays around the character who murders the tyrant, Brutus in Julius Caesar and Hamlet in the play of that name.
Brutus kills Caesar, dealing the decisive blow during the historically based account of senators murdering the Roman leader. Caesar was a father figure to Brutus in the play, and in real life. What the play does not mention is that Caesar had an affair with Brutus’ mother, and he was even rumoured to be the father of Brutus, though that seems to be very unlikely. The play shows Caesar’s special horror when he sees that Brutus is striking him.
Hamlet kills the tyrant Claudius, who unlike Caesar is only a tyrant in the sense that he may have come to his position unjustly, not that he has created a new power in the state which undermines previous limitations on the powers of one man. Claudius is the paternal uncle of Hamlet, who inherits the throne when the king his brother died. Claudius marries the king’s widow, Gertrude who is also Hamlet2s mother, very soon after the death.
Both Hamlet and Brutus kill father figures, who are not the biological father but who are very powerful symbolic fathers.
Hamlet sees the ghost of his father early in the play, who tells him that Claudius killed him. Very near the end of Julius Caesar, Brutus is reported to have seen the ghost of Caesar, preceding Brutus’ suicide which results from his military defeat by the followers of Caesarist party. Hamlet’s father says that Claudius poured poison into the porches of his ear. Just before the death of Brutus, Messala refers to thrusting this report into his ears which will be as welcome as piercing steel and envenomed darts, because it refers to the death of Cassius. So the idea of thrusting something poisonous into the ears (a possible play by Shakespeare on his own name) appears in relation to the father who was killed by the tyrant-substitute father in Hamlet, and in relation to the killer of the tyrant substitute-father in Julius Caesar. Verbal patterns seem to link the victim of tyranny/the avenger murderer of the tyrant with a poison in the ears which links them to the name of the author. The real father and the substitute tyrant father appear in dreams to the tyrannicide.
The death of both tyrannicides is marked by eulogy, for Brutus the eulogy come from Brutus’ enemy Mark Anthony, while for Hamlet the eulogy comes from his friend Horatio, but then right at the end from the invading Norwegian prince Fortinbras. Both are recognised as great leaders by those who were their rivals, though Mark Anthony is the most intense rival, who is competing with Brutus for control of the memory of the joint substitute father.
The two plays appear to have been first performed in 1599 (Julius Caesar) and 1602 (Hamlet), so are close together and unsurprisingly elements from the earlier one are reused and rearranged in the later one. The interest in writing plays about the murder of tyrants at this time is rather peculiar, since Shakespeare was living under a monarch, Queen Elizabeth who might feel sensitive on the issue. She may have felt excused from accusations of tyranny on the grounds that she recognised Parliament as the source of laws and taxes, and that even in her executive function she ruled through a council. Nevertheless she was a monarch with serious powers, who had the politically dangerous executed including her own cousin, Mary Queen of Scots. In 1601, Robert Devereux, Earl of Essex attempted to overthrow the government, and the uprising in London was inaugurated by a performance of Shakespeare’s Richard II, which refers to the overthrow of that king by Henry Bolingbroke, who became Henry IV. As Carl Schmitt points out in Hamlet or Hecuba, Hamlet could have been a very troubling play for James I, since it refers to a queen married to the man who murdered her husband, which looks like a reference to James’ mother, Mary Queen of Scots. The play was first performed before James, already James VI of Scotland became James I of England, but it was widely understood towards the end of Elizabeth’s reign that James would be offered the throne on her death.
There is no reason to believe that Shakespeare ever fell from royal favour, or even came close, so he was very successful in separating his plays about the overthrown of bad rulers from any criticism of his monarch, even if others chose to use them in that way. The plot of Julius Caesar is not as immediately applicable to events of Shakespeare’s own time as Hamlet, but the topic of republican plots against a monarchical figure, and Caesar was the model for Roman emperors, and then subsequent European kings and emperors. The educated at that time, if educated enough to study Latin, would have read Cicero a political theorist of republicanism, an outspoken enemy of Mark Anthony in the Senate, and a friend of Brutus. Cicero was the model of Latin composition under the Roman Emperors, so the separation of Cicero from the radical application of his political ideas goes right back almost to his death. It all seems a bit extraordinary that Shakespeare could have played with this on stage, but I think that the English monarchs of the time were so invested in the idea that their use of power was wise and moderate, in line with national custom and law, that they did feel alarm at stories of tyrannicide and certainly did not want to be seen to have a negative attitude, even after Devereux had used a Shakespeare play in his own coup. Even in the late 17th century Charles II, whose father Charles I was executed under the English Commonwealth (Republic) did not feel moved to repress plays about tyrannicide.
Elizabeth was a member of the Tudor dynasty, and her grandfather Henry ‘Tudor’ VII had overthrown Richard III, so perhaps felt that justified tyrannicide had to be recognised even if only in acknowledgement of past events. Poking about in the realms of psychological speculation, she may have believed her father Henry VIII (portrayed positively by Shakespeare in his play of that name) was an evil tyrant for executing her mother, Anne Boleyn (another reason why Gertrude in Hamlet might be an awkward figure) and found the idea of killing off tyrannical father figures rather cathartic, a feeling James VI/I may have had in relation to his own own mother’s third husband (James was the son of the second husband).