Westminster Hall, the oldest existing part of the Palace of Westminster, was erected in 1097, at which point it was the largest hall in Europe. The roof was probably originally supported by pillars, giving three aisles, but during the reign of King Richard II, this was replaced by a hammerbeam roof by the royal carpenter Hugh Herland, "the greatest creation of medieval timber architecture", which allowed the original three aisles to be replaced with a single huge open space, with a dais at the end.
Westminster Hall has the largest clearspan medieval roof in England, measuring 20.7 by 73.2 metres (68 by 240 ft). It has served numerous functions. It was primarily used for judicial purposes, housing three of the most important courts in the land: the Court of King's Bench, the Court of Common Pleas and the Court of Chancery. In 1875, these courts were amalgamated into the High Court of Justice, which continued to meet in Westminster Hall until it moved to the Royal Courts of Justice in 1882. Westminster Hall has also served ceremonial functions. From the twelfth century to the nineteenth, coronation banquets honouring new monarchs were held here.