When Europeans began fielding crossbows on battlefields in earnest during the 10th century AD, not only were the triggers more cumbersome, the bows were made of wood. However, by the 13th century European crossbows began transitioning to composite bows as well, increasing their draw weight. While still utilizing the rolling nut mechanism, 13th century European composite crossbows were probably not much worse compared to the Chinese crossbow, if at all, in terms of draw-weight. From the 13th century onward, European crossbows made use of spanning mechanisms not seen in China such as the pulley, gaffle, cranequin, and screw. Furthermore, 14th century European crossbows could be made of steel, increasing their draw weights beyond even the heaviest Chinese infantry crossbow. These were accompanied by the cord pulley spanning device. However, the power stroke of the European crossbows remained much lower than that of Chinese crossbows (typically one third of the powerstroke), which limited their power despite increasing draw weights.