(Marcus Brutus.)
The drama puts it thus:
Brutus. Give me your hands all over, one by one.
Cassius. And let us swear our resolution.
Brutus. No, not an oath: if not the face of men
The suffrance of our souls, the time’s abuse,
If these be motives weak, break off betimes:
(II. i. 112.)
and so on through the rest of his magnificent speech that breathes the pure spirit of virtue and conviction. The nobility of Brutus that is reverenced by all, the conspiracy of Romans that is safe-guarded by no vows, move Plutarch’s admiration, but he does not associate them. Shakespeare traces the one to the other and views them as cause and effect.
Shakespeare thus greatly alters the character of Plutarch’s narrative by his ceaseless activity in sifting it, ordering it afresh, and reading into it an internal nexus that was often lacking in his authority. But this last proceeding implies that he also makes additions, and these are not only numerous and manifold, but frequently quite explicit and very far-reaching. It is important to note that Plutarch has furnished nothing more than stray hints, and often not even so much, for all the longer passages that have impressed themselves on the popular imagination. Cassius’ description of the swimming match and of Caesar’s fever, Brutus’ soliloquy, his speech on the oath, his oration and that of Mark Antony, even, when regarded closely, his dispute with Cassius, are all virtually the inventions of Shakespeare. The only exception is the conversation with Portia, and even in it, though the climax, as we have seen, closely reproduces both Plutarch’s matter and North’s expression, the fine introduction is altogether Shakespearian.