Sailing ships prior to the mid-19th century used wood masts with hemp-fiber standing rigging. As rigs became taller by the end of the 19th Century, masts relied more heavily on successive spars, stepped one atop the other to form the whole, from bottom to top: the "lower mast", "top mast", and "topgallant mast". This construction relied heavily on support by a complex array of stays and shrouds. Each stay in either the fore-and-aft or athwartships direction had a corresponding one in the opposite direction providing counter-tension. Fore-and-aft the system of tensioning started with the stays that were anchored in front each mast. Shrouds were tensioned by pairs deadeyes, circular blocks that had the large-diameter line run around them, whilst multiple holes allowed smaller line—"lanyard"—to pass multiple times between the two and thereby allow tensioning of the shroud. After the mid-19th century square-rigged vessels were equipped with steel-cable standing rigging.