During this period flourished Æschylus and Sophocles, Euripides and Aristophanes, dramatists; Pindar, a lyrical poet; Herodotus and Thucydides, historians; Xenophanes, Heraclitus, Empedocles, Anaxagoras, and Socrates, philosophers (reasoners upon the nature of the human mind, and upon man’s immortal destiny). In this period also, under the administration of Pericles (from 458 to 429 B. C.), sculpture and architecture attained their perfection. It was then that Phidias executed those splendid works, statues of the gods and goddesses, which excited the admiration of the world, and which succeeding artists have in vain endeavored to rival. While Athens had extended its power over a great part of the coasts of the Ægean Sea, and increased its trade and commerce by every available means, it had also become a city of palaces and temples, whose ruins continue to be the admiration of ages for their grandeur and beauty. It is understood that the Greeks had acquired their knowledge of architecture from the Egyptians; but they greatly excelled them in the elegance of their designs, and are in a great measure entitled to the character of inventors in the art. The beauty of the Corinthian pillar, for example, has never been excelled either in ancient or modern times. After the surrender of Athens to the Spartans (404 B. C.), the democratic constitution was abolished, and the government was intrusted to thirty persons, whose rapacious, oppressive, and bloody administration ere long procured them the title of the Thirty Tyrants. The ascendancy of these intruders was not, however, of long duration. Conon, assisted privately by the Persians, who were desirous of humiliating the Spartans, expelled the enemy, and reëstablished the independence of his country. About seventy years later a new source of agitation throughout Greece was caused by the warlike projects of Alexander, king of Macedon, usually styled.