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.
Ch. 1 : The Great Tower : Norman and Early Plantagenet Castles - Medieval castles (2005)