Infantry in the Middle Ages heavy toll on the English invaders of their lands. Adapted by the English, the longbow was nevertheless a difficult weapon to master, requiring long years of use and practice. Even bow construction was extended, sometimes taking as much as four years for seasoned staves to be prepared and shaped for final deployment. A skilled longbowman could shoot 12 arrows a minute, a rate of fire superior to competing weapons like the crossbow or early gunpowder weapons. The nearest competitor to the longbow was the much more expensive crossbow or Arbalest, used often by urban militias and mercenary forces. It required
Weapon by all major industrial powers. Many modern military weapons, particularly ground-based ones, are relatively minor improvements of weapon systems developed during World War II. "See military technology during World War II for a detailed discussion." World War II however, perhaps marked the most frantic period of weapons development in the history of humanity. Massive numbers of new designs and concepts were fielded, and all existing technologies were improved between 1939 and 1945. The most powerful weapon invented during this period was the atomic bomb, however many other weapons influenced the world in ways overshadowed by the importance of nuclear weapons.