Why does shakespeare include the feast of lupercal in julius ceaser?
In my opinion, the key to including the feast is that it is a communal event, in which Romans as a community become involved in the Tragedy by offering to Caesar the crown of emperor / king. This implicates the people of Rome in the tragedy (i.e. the death of the Roman republic). In this way the personal tragedy (Brutus’ personal betrayal of the laws of Rome and of Caesar), is mirrored in by the community, who have already abandoned the ideals of the Republic in offering Caesar the crown.