Before Hiero the Carthaginians relied heavily upon a system of hiring mercenary armies from foreign nations to fight for them. After a war these mercenaries would be paid and they would disperse. Each mercenary unit was expected to bring its own weapons and equipment and to receive its own training. This made a mercenary army very diverse as many of its soldiers carried different equipment and came from different countries, making them culturually and ethnically different. It also meant that each invididual unit had its own strengths and weaknesses and had to be positioned according to the enemy's troop positions. This was difficult against opponents who were keen to suddenly switching their troop positions (such as the Scipios did at the Battle of Ilipa during the Scipian Rebellion). Gene