Panhellenion
The Panhellenion or Panhellenium was an institution of cities established in the year 131-132 AD by the Roman Emperor Hadrian while he was touring the Roman provinces of Greece.
Hadrian was philhellenic, and idealized the Classical past of Greece. The Panhellenion was part of this philhellenism, and was set up, with Athens at the centre, to try to recreate the apparent "unified Greece" of the fifth-century, when the Greeks took on the Persian enemy.