© Erich Lessing

WORLD CONQUEROR. At the age of 30, Alexander the Great ruled an empire that stretched from his homeland of Greece to Egypt in the south and to India in the east. Showing Alexander on his horse Bucephalus in battle against Darius III of Persia, this mosaic comes from Pompeii, Italy, and dates to c. 100 B.C.E. After Alexander died, his general Ptolemy I Soter became the ruler of Egypt and even declared himself pharaoh, thus establishing the Ptolemaic dynasty that governed Egypt for nearly 300 years.