Tiberius and Caius Gracchus
Plutarch
Plutarch. Plutarch's Lives, Vol. X. Perrin, Bernadotte, translator. Cambridge, MA: Harvard University Press; London: William Heinemann Ltd., 1921.
Now, just as, in spite of the likeness between Castor and Pollux as they are represented in sculpture and painting, there is a certain difference of shape between the boxer and the runner, so in the case of these young Romans, along with their strong resemblance to one another in bravery and self-command, as well as in liberality, eloquence, and magnanimity, in their actions and political careers great unlikenesses blossomed out, as it were, and came to light. Therefore I think it not amiss to set these forth before going further.