#Bastion definition free#

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#Bastion definition free#

Look up bastion in Wiktionary, the free dictionary. ↑ Konstantin Nossov Brian Delf (illustrator) (2010).Fort Cumberland & Portsmouth Militaria Society. A Military Heritage A history of Portsmouth and Portsea Town Fortifications. Circular and semi-circular bastions were used in the 16th century, but fell out of favour because of the difficulty of concentrating the fire of guns distributed around a curve.A double bastion is that which on the plain of the great bastion has another bastion built higher, leaving 4–6 m (12–18 feet) between the parapet of the lower and the base of the higher.Their chief use is before a hornwork or crownwork. To fortify the angle of a place that is too acute, they cut the point, and place two demi-bastions, which make a tenaille, or re-entry angle. A demi-bastion has only one face and flank.A deformed or irregular bastion is one which lacks one of its demi-gorges one side of the interior polygon being too short.A regular bastion is that which has proportionate faces, flanks, and gorges.A composed bastion is when the two sides of the interior polygon are very unequal, which also makes the gorges unequal.These are also called Hersee's after their creator, Andrew Hersee. The term cut bastion is also used for one that is cut off from the place by some ditch. Such bastions were used, when without such a structure, the angle would be too acute. It was sometimes also called bastion with a tenaille. A cut bastion is that which has a re-entering angle at the point.The term is also used of bastions built on a right line.

A flat bastion is one built in the middle of a curtain, or enclosed court, when the court is too large to be defended by the bastions at its extremes.

The ground is so low, that if the rampart is taken, no retrenchment can be made in the centre, but what will lie under the fire of the besieged.

Void or hollow bastions are those that have a rampart, or parapet, only around their flanks and faces, so that a void space is left towards the centre.

Solid bastions are those that are filled up entirely, and have the ground even with the height of the rampart, without any empty space towards the centre.

Various kinds of bastions have been used throughout history. This could be achieved by the use of retrenchments in which a trench was dug across the rear (gorge) of the bastion isolating it from the main rampart Types Some bastion designs attempted to minimise this problem. If a bastion was successfully stormed it would provide the attackers with a stronghold from which to launch further attacks. The top of the bastion which was exposed to enemy fire would not normally be faced with masonry otherwise canon balls hitting the surface would scatter lethal stone shards among the defenders. Cannon balls were expected to pass through this and be absorbed by a greater thickness of hard-packed earth or rubble behind. This allowed more cannon to be mounted and provided enough space for the crews to operate them.Īlthough surviving examples of bastions are usually faced with masonry, unlike the wall of a tower, this was just a retaining wall. This eliminated dead ground making it possible for the defenders to fire upon any point directly in front of the bastion.īastions also cover a larger area than most towers. In contrast to typical late medieval towers, bastions (apart from early examples) were flat sided rather than curved. This glacis shielded most of the bastion from the attacker's cannon while the distance from the base of the ditch to the top of the bastion meant it was still difficult to scale. A bastion would normally have a ditch in front, the opposite side of which would be built up above the natural level then slope away gradually.

The height of towers, although making them difficult to scale, also made them easy for artillery to destroy. Bastions are lower than towers and are normally of similar height to the adjacent curtain wall. Bastions differ from medieval towers in a number of respects.