Where is the portcullis on a castle
The weakest place in the defence was where people had to come and go, that is the entrance through the walls. This was defended by two guard towers and some kind of very strong gate. The gate was often defended by a moat and drawbridge. But there were other lines of defence, too.
The space between the guard towers had slits in the tower walls where people could shoot arrows at anyone who attacked. Then there were holes above through which boiling water could be poured. These were called murder holes. The portcullis was ready to be released at the first sign of danger. The castle Portcullis was particular important when a medieval castle found itself under surprise attack as a barrier could quickly be put in place whilst the castle defences were organised.
The Portcullis was first introduced in Roman times before the medieval period that started around , although similar devices were used the portcullis did not become incorporated into the castle design until around the 12th century. The final stage of a portcullis development found it being incorporated into the actual drawbridge, at this stage the portcullis would work in tandem with the drawbridge mechanism.
The Portcullis was often used as a counterweight for the drawbridge. The Portcullis was used to protect a castles entrance from attack and was usually positioned at the front of a castles gatehouse, it created yet another barrier to protect the people inside the castle from enemy attack.
Portcullis were made of heavy wood, to improve the design metal plating was added to the spiked ends and in later medieval times the whole of the portcullis was plated with metal. Portcullis fortified the castle entrance and were winched into place by the gatehouse guards, the chains or ropes were pulled which raised the Portcullis along vertical grooves built into the stone at either side of the entrance. Using this winching mechanism the Portcullis could be raised quickly, but the main advantage was how quickly the Portcullis could be released.
Each portcullis was mounted in vertical grooves in castle walls and could be raised or lowered quickly by means of chains or ropes attached to an internal winch - often in the guardroom above. There would often be two or more portcullises to the main entrance. The one closest to the inside could be closed first and then the one farthest away. In this way the enemy enemy could be trapped in a killing area. There were often arrowslits in the sides of the walls, and murder holes above, enabling archers and crossbowmen to eliminate the trappedattackers.
The portcullis is a well known feature of castle and city gates. The example on the left is from Puivert. That on the right from Aigues Mortes. The name means "running ie sliding" gate. Some were made in iron, some in wood. In the royal badge now appropriated by the House of commons shown above right, you can see the hoisting chains, usually concealed from sight, here hanging loose.
The hoisting equipment, a geared windlas, is located in the room above the gateway, which was often the guardroom. It made sense to have your gards as near as possible to the fortification's classic weakspot.
Medieval castles were usually defended by a ditch or moat, crossed by wooden bridge. In early castles the bridge might be designed to be destroyed or removed in the event of an attack, but drawbridges became common. A typical arrangement was to have the drawbridge immediately outside a gatehouse, consisting of a wooden deck with one edge hinged or pivoting at the gatehouse threshold, so that in the raised position the bridge would be flush against the gate, forming an additional barrier to entry.
It would be backed by one or more portcullises and gates. Access to the bridge could be resisted with missiles from machicolations above or arrow slits in flanking towers. The bridge or sometimes just the end part of the bridge - as at Doornenburg shown on the right would be raised or lowered using ropes or chains attached to a windlass in a chamber in the gatehouse above the gate-passage.
Only a very light bridge could be raised in this way without any form of counterweight, so some form of bascule arrangement is normally found. The bridge may extend into the gate-passage beyond the pivot point, either over a pit into which the internal portion can swing providing a further obstacle to attack , or in the form of counterweighted beams that drop into slots in the floor.
The raising chains could themselves be attached to counterweights; in some cases a portcullis provides the weight, as at Alnwick. By the 14th Century a bascule arrangement was provided by lifting arms called "gaffs" above and parallel to the bridge deck whose ends were linked by chains to the lifting end of the bridge; in the raised position the gaffs would fit into slots in the gatehouse wall "rainures" which can often still be seen, as at Herstmonceux Castle.
Inside the castle the gaffs were extended to bear counterweights, or might form the side-timbers of a stout gate which would be against the roof of the gate-passage when the drawbridge was down, but would close against the gate-arch as the bridge was raised. Barbicans are defensive structures controlling access to a gateway. They are fortified outposts or gateways, typically forming the outer defence to a fortified city or castle, The Barbican in London marks the site of a barbican defending an important entrance to the City of London.
Barbicans sometimes take the form of a tower situated over a gate or bridge which was used for defensive purposes. Usually barbicans were situated outside the main line of defences and connected to the city walls with a walled road called the neck. With improvements in artillery in the 15th century, barbicans lost their importance. Few barbicans were built in or after the 16th century. The old Cite of Carcassonne possesses no fewer than four barbicans.
They are all different and give a good idea of the range of structures described as barbicans. The main entrance to Carcassonne was the Narbonne Gate, a substantial gate in the inner curtain wall.
It was defended by a barbican, shown on the right, in the outer curtain wall. Photograph of the Barbican at the chateau Comtale at Carcassonne, taken from the hourdes on top of the chateau wall.
0コメント