The Kingdom of Macedon possessed one of the greatest armies in the ancient world. It is reputed for the speed and efficiency with which it emerged from Greece to conquer large swathes of territory stretching from Egypt in the west to India in the east. Initially of little account in the Greek world, it was widely regarded as a second-rate power before being made formidable by Philip II, whose son and successor Alexander the Great conquered the Achaemenid Empire in just over a decade's time.