Our history begins on the African savannah. Economy was based on meat. Meat was something to build an economy on: it was available in limited quantity and obtaining it required special skills. Meat, in its original form either ran away very fast or, even worse, fought back. So was the cow invented -- thus the importance of meat as the base of the economy dwindled and now the land where you could grow your cow was more important. So the land became the base of wealth and land was available in limited quantities and soon every land belong to some thus trying to obtain it again lead to conflict.