Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Humans lived in the region that is now Burma as early as 11,000 years ago, but archeological evidence dates the first settlements at about 2500 BCE with cattle rearing and the production of bronze. By about 1500 BCE, ironworks were in existence in the Irrawaddy Valley but cities, and the emergence of city states, probably did not occur till the early years of the Common era when advances in irrigation systems and the building of canals allowed for year long agriculture and the consolidation of settlements.