In the first 38 lines, the tribunes address the mechanicals wanting to know what professions they are and why they are not at work:
Fla. Thou art a Cobler, art thou?
Cob. Truly sir, all that I liue by, is with the Aule: I meddle with no Tradesmans matters, nor womens mat-ters; but withal I am indeed Sir, a Surgeon to old shooes: when they are in great danger, I recouer them. As pro-per men as euer trod vpon Neats Leather, haue gone vp-on my handy-worke.
Fla. But wherefore art not in thy Shop to day? Why do'st thou leade these men about the streets?
Cob. Truly sir, to weare out their shooes, to get my selfe into more worke. But indeede sir, we make Holy-day to see Caesar, and to reioyce in his Triumph.
Shakespeare includes this interaction of the Cobbler and Murellus as a spoof, one that is sadly lost on a modern audience. The play on stage prior to “Julius Caesar” back in 1599 was entitled “The Shoemaker’s Holiday”; the lead character is embroiled in both tradesman’s and women’s matters. The actors for both productions were probably the same; both productions may have been shown together on a given day. The first audiences seeing these productions back to back would have realized Will was injecting a bit of humor in his passing reference to the preceding play before getting down to the serious business of slaying Caesar.
For the most part, this scene is the beginning since it shows how fickle the crowd in Rome can be. They are celebrating Caesar when not so long ago they celebrated Pompey. The play is brought full circle when Caesar is dead and in one small cross-section of time the same crowd has cheered and celebrated both Brutus and Antony.
So, to answer you simply, Shakespeare uses this scene to both give background information and to foreshadow what is to come in the nearby future.
The opening scene of Julius Caesar is expository – it sets up the context for what is to follow and introduces the issues that will be explored.
It consists of a confrontation between two tribunes, Roman officials, and a group of commoners. The tribunes Flavius and Marullus are outraged to see the commoners neglecting their work and parading about the streets to celebrate Caesar’s victory. This makes them especially angry because the victory in question has not been against a foreign foe but against Caesar’s Roman rival Pompey, who in his day had also been the darling of the Roman crowd. Marullus accuses the commoners of being unfaithful and fickle:
You blocks, you stones, you worse than senseless things!
O you hard hearts, you cruel men of Rome,
Knew you not Pompey?
He succeeds in making them ashamed of themselves, and after they depart, in a much more sober mood, the two tribunes agree to go around the streets, force the commoners to go home and stop celebrating, and take down the imperial decorations that have been put on Caesar’s statues.
This scene makes several important points:
- There is a popular demand for Caesar to become an absolute ruler.
- Caesar is a hero to the masses, but the opinion of him held by some at least of the upper classes is much less favorable.
- The Roman crowd is easily swayed by oratory and can be “turned around” at the drop of a hat.
The action shown here foreshadows that later seen at Caesar’s funeral.