Both have survived, on their own terms, for roughly two millennia—which means permanence was never really about the material at all. It began as a pagan temple, dedicated to all the gods of Rome, and became, centuries later, a Christian church. Still, walk through Rome, or Florence, or any European city built on Roman bones, and you feel the payoff of that philosophy. Rome wanted the object to survive because the object was the idea, made flesh. Maybe the real lesson of comparing the Pantheon to Ise is not which building will outlast the other.