The Mongol Empire considered horses as an important factor to its success and tailored other weapons to them. The bow and arrow was created to be light enough to attack enemies while on horseback. The Mongols used composite bows made from birch, sinew and the horns of sheep. This made sturdy but light bows. Three types of arrows were created for different purposes. The most common arrow used for warfare was the pointed iron head, which could travel as far as 200 metres. If a soldier wanted to slice the flesh of the opposing member, the v-shaped point was used. In times of war, soldiers would shoot the third form of arrow with holes, used for signalling. By listening to the whistling sounds that were produced by this type of arrow, soldiers were able to march in a required direction.