Who were they and what was the outcome of the battle/war? How significant was their role?
The First Battle of Meggido is believed to be the first battle ever accurately recorded, and took place around 1469BCE. Not only was it the first battle recorded, it also included mercenary involvement. This was an important battle, as it helped to revive Egyptian power as well as established an Egyptian presence in Asia.
Alan Axelrod's book, Mercenaries: A Guide to Private Armies and Private Military Companies states that the Egyptian army was too large to be made up of just Egyptians, due to their population at the time, and that they must have outsourced help from elsewhere. Many of the mercenaries were vagabonds, known as The Sea Peoples.