Lives of the Noble Greeks and Romans by the Greek historian Plutarch. Lives was translated into French by writer Jacques Amyot in the early 1560’s. Thomas North then translated it into English, with his first edition appearing in the late 1570’s.
As was his want, Shakespeare would steal wholesale, then change things to his purposes. Shakespeare’s version of Coriolanus’ speech to Aufidius and the other Volscians into their camp:
To thee particularly and to all the Volsces
Great hurt and mischief; thereto witness may
My surname Coriolanus. The painful service,
The extreme dangers, and the drops of blood
Shed for my thankless country are requited
But with that surname–a good memory,
And witness of the malice and displeasure
Which thou shouldst bear me. Only that name remains.
The cruelty and envy of the people,
Permitted by our dastard nobles, who
Have all forsook me, hath devoured the rest,
And suffered me by th’ voice of slaves to be
Whooped out of Rome.
sounds suspiciously like the corresponding speech from North’s translation of Plutarch:
That all said, it seems that Shakespeare did make some changes to Plutarch, moving some of the incidents and events around, and expanding on some of the characters, like Menenius and the women in Martius’ life: mother Volumnia and wife Virgilia, as well as inventing some aspects as the main character’s internal conflicts.
There are some critics that feel that there’s a bit of a literary pick-pocketing of Livy’s Ab Urbe condita, and William Camden’s Remaines of a Greater Worke Concerning Britaine (1605), but this is less than certain.