In his 1594 Memorie di varie antichità trovate in diversi luogia della Città di Roma, Flaminio Vacca remembers a “Seneca di marmo nero” being found with some other ancient fragments on an estate in Rome. This was probably the life-size statue you see above. It is mentioned in a poem about the Borghese collection in 1613, and Rubens must have seen it when he traveled through Italy in 1600–08, since he based his own painting of the dying Seneca on it.
Why Seneca? Well, first of all, at the time Seneca was considered one of the most important Roman writers, and as a philosopher on the same level as Plato and Aristotle, so there was the expectation that there would have been lots of statues of him in ancient Rome. The legs of this statue end abruptly ad mid-thigh, it was obviously meant to represent a man standing in water, and Seneca killed himself in a bath-tub.
So a basin was made for the statue to stand in, the surface reddened as if the water was mixed with blood. The arms are restored too, as is the alabaster belt. The head with the inlaid enamel eyes is original.
In 1807, a large part of the Borghese collection, including the Seneca, was sold to the French government under some pressure from Napoleon and put into the Louvre, where it still stands (Room A). In 1813, the duble herma of Seneca and Socrates was found, making it clear that this was not a statue of the stoic philosopher. It is now known as the Old Fisherman, or Borghese Fisherman.
Photograph by Wally Gobetz.