The stream of Time, irresistible, ever moving, carries off and bears away all things that come to birth and plunges them into utter darkness, both deeds of no account and deeds which are mighty and worthy of commemoration; as the playwright [Sophocles] says, it 'brings to light that which was unseen and shrouds from us that which was manifest.' Nevertheless, the science of History is a great bulwark against this stream of Time; in a way it checks this irresistible flood, it holds in a tight grasp whatever it can seize floating on the surface and will not allow it to slip away into the depths of Oblivion.