Actually art-historians suspected this a long time ago from the paint flecks buried in the cracks of ancient sculptures, but orthodoxies die hard. Now the notion that Greek antiquities were polychromatic to the point of gaudiness is gaining acceptance.
The first picture is one that I took in 2004 at the British Museum of the Elgin Marbles taken from the Acropolis, from the running frieze. The next photo is a color rendering of possible coloration.
You can bet that looking up at the Acropolis from the streets below in Athens must have been a delight to see some 2,500 years ago.
And once again a hat tip to Kottke.org, http://kottke.org/10/08/painted-greek-statues.
Imagine what Michelangelo's David or Bernini's Ecstasy of St. Teresa would be had they been modeled on and inspired by full color antiquities. We'd all be living now in a very different post-Renaissance world.