Chat or chatchasteil) was a movable pent-house used to protect besiegers when approaching a wall or gateway, for the purpose of sapping, mining or direct attack, or to cover a ram or other battering-engine.
The word is also sometimes applied to a heavy timber fitted with iron spikes or projections to be thrown down upon besiegers, and to the large work known as a "cavalier."
The famous defence of Haarlem, lasting through the winter of 1572 to July 1573, cost the besiegers 12,000 lives, and gave of the insurgent provinces time to breathe.
In particular he soon put the artillery of the besiegers in good order.
The besiegers were no sooner in the city, than they were besieged in their turn by Kerbogha; and the twenty-five days which followed were the worst period of stress and strain which the crusaders had to encounter.