About six centuries Before Christ, the land of most of the modern-day Afghanistan was captured by the Persian Emperor, Darius I. Bactra, the present-day city of Balkh, became the capital of the kingdom. After the three centuries of Persian rule, the Greeks under their king, Alexander the Great, overran this land. The Greeks established an independent mini-Greek kingdom of Bactria with its capital at Balkh. It was called "the mother of cities."