 Complete the following phrase:  Clermont ranks among the oldest cities of France. The first known mention was by the Greek geographer Strabo, who called it the metropolis of the Arverni meaning their oppidum, civitas or tribal capital. The city was at that time called Nemessos  a Gaulish word for a sacred forest, and was situated on the mound where the cathedral of Clermont-Ferrand stands today. Somewhere in the area around Nemossos the Arverni chieftain Vercingetorix later to head a unified Gallic resistance to the Roman invasion led by Julius Caesar was born around 72 BC. Also, Nemossos was situated not far from the plateau of Gergovia, where Vercingetorix repulsed the Roman assault at the 