Damascus is first documented as an important city during the arrival of the Aramaeans, a Semitic people, in the 11th century BC. By the start of the first millennium BC, several Aramaic kingdoms were formed, as Aramaeans abandoned their nomadic lifestyle and formed federated tribal states. One of these kingdoms was Aram-Damascus, centered on its capital Damascus. The Aramaeans who entered the city without battle, adopted the name "Dimashqu" for their new home. Noticing the agricultural potential of the still-undeveloped and sparsely populated area, they established the water distribution system of Damascus by constructing canals and tunnels which maximized the efficiency of the river Barada. The same network was later improved by the Romans and the Umayyads, and still forms the basis of the water system of the old part of the city today. The Aramaeans initially turned Damascus into an outpost of a loose federation of Aramaean tribes, known as Aram-Zobah, based in the Beqaa Valley.