A structure on which woven cloth is manufactured comprising two more or less vertical supports (often set in the ground) with a horizontal beam across the top. The warp threads are tied to the cross-beam so that they hang down, thus allowing the weaver to move a horizontal shed rod between alternating sets of the warp in order that a shed is opened up for the weft to be threaded through. The warp threads were tensioned by loomweights. The upright loom was commonly used in antiquity, traces of them being known in Europe from the middle Bronze Age onwards.