The gatehouse is a house like spot where someone can lower

or raise the portcullis. They are  a look out for enemies and to see if they have to let people in or out the castle.  

The most important part of a castle as far as its defense was concerned, the entry being the weakest point. Older ones were little more than a strong arch with heavy iron-bound wooden gates and drawbars and a guard chamber on top or to the side. Later on, flanking towers were added to the gateway, and Portcullises and Drawbridges. Where as the Keep was a passive defense, the gatehouse was right up in front, and became the most important part of building in the later castles.


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