The militia (fyrd) is a non-professional military force made up of freemen, which can be called up by the ruler, especially to defend against a sudden attack. The militiamen are responsible for maintaining their own equipment and skills, and are expected to drill as a body regularly. The militia is not customarily used offensively outside their own domain, and their usefulness in such a campaign would be questionable at best.
Even when it is not called up, the militia is responsible for patrolling its home region. Each militiaman serves in this capacity once per week.