Julius Caesar was a master politician who worked energetically to achieve the adoration of the masses. He did not seek just the approval and adoration of the upper class but of all classes. He would certainly have had an air of authority, a way of speaking and behaving that commands others to believe you are in charge.
In this scene, Caesar ceremoniously, or with pomp and ritual, enters a crowded public square where a feast is already in progress. His wives and other prominent Romans file in behind him showing that clearly he is the focal point. As soon as Caesar speaks, the crowd is ordered to silence and all attention is on him. The others in the scene answer him respectfully with phrases such as "Caesar, my Lord?" At one point Antony says to him: "When Caesar says do this, it is done!" These statements and behaviors of obedience and attention toward Caesar show that the crowd believes he is the authority. Caesar's actions upon entering so ceremoniously command this type of response from them and prove that he has an air of authority about him.