Stone towers appeared early in the Loire River valley. The massive ruin at Langeais, recently dated 992, was once a broad tower with four corner turrets. Today it stands in the park of a fifteenth-century chateau. Not far off, at Loches, the tower is the earliest surviving great tower to combine within its walls a hall, the lord’s chamber, and a chapel. Recent analysis of the wood used in the original building has dated this tower between 1012 and 1035. Meanwhile, in England, as we have seen, during the first years after the Norman invasion, William and his men depended on hastily built earth and timber defenses but replaced the wooden castles with stone as soon as the earth had compacted. Masonry required good stone quarries and quarry men, powerful ox teams to transport the material, and skilled stonemasons to construct the walls and vaults. Stone castles became a heavy burden on the people (Documents 13–19).