During the reign of Henry III the Assize of Arms of 1252 required that all "citizens, burgesses, free tenants, villeins and others from 15 to 60 years of age" should be armed. The poorest of them were expected to have a halberd and a knife, and a bow if they owned land worth more than £2. This made it easier for the King to raise an army, but also meant that the bow was a weapon commonly used by rebels during the Peasants' Revolt. From the time that the yeoman class of England became proficient with the longbow, the nobility in England had to be careful not to push them into open rebellion.