This statue in the Vatican‘s Pio Clementino Museum may be the most influential of them all…
Michelangelo admired it, as did Donatello before him, and Pliny the Elder long before them; this latter attributed it to three sculptors from Rhodes, but we don’t know who commissioned it, nor when it was sculpted, nor whether there was an earlier, bronze statue of which this is a mere marble copy.
It depicts Laocoön and his sons being attacked by sea serpents, as punishment by Athena for trying to warn the Trojans about that horse the Greeks had left. It has been described as “the prototypical icon of human agony”