Bala, Sumerian for "exchange", is the method by which the Ur III dynasty of Mesopotamia collected goods such as livestock, grain, labor and craft products from its provinces. Individuals of all rank were expected to contribute to this system. These taxes were used to fund building projects within the kingdom such as the building of canals which were vital in this area because the agriculture in this area was irrigated by water from the Tigris and Euphrates rivers. Those projects were built by Gurush/Geme (Sumerian), men and women workers respectively, paid using goods collected from the tax system. The provinces in the Ur III Empire such as Girsu, Umma and Lagash contributed materials according to the nature of goods they produced, their size and the amount of goods they could produce. Fo