The Age of Disorder) Feudalism 391 protecting their soldiers when they crept up to the walls with their battering-rams and pickaxes in the hope of making a breach and so getting into the town. But the Ger- man barbarians who overran the Roman Empire were unaccus- tomed to these ma- chines, which therefore had fallen into disuse. But the practice of taking towns by means of them was kept up in the Eastern Empire, and during the Cru- sades, which, as we shall see, began about 1 100 (see Chapter XIX, below), they were introduced once more into western Europe, and this is the reason why stone castles be- gan to be built about that time. A square tower (Fig. 156) can, how- ever, be more easily attacked than a round tower, which has no corners, so a century later round towers be- came the rule and continued to be used until about the year 1500, when gunpowder and cannon had become so common that even the strongest castle could no longer be defended. Fig. 156. Tower of Beaugexcv This square donjon not far from Orleans, France, is one of the very earliest square towers that survive. It is a translation into stone of the wooden donjons that prevailed up to that time. It was built about 1 100, just after the beginning of the First Crusade. It is about 76 by 66 feet in size and r 1 5 feet high
