Blonde Girl Posing In A Castle On The Table

A moat was a defensive ditch with steep sides, and could be either dry or filled with water. Its purpose was twofold; to stop devices such as siege towers from reaching the curtain wall and to prevent the walls from being undermined. Water moats were found in low-lying areas and were usually crossed by a drawbridge, although these were often replaced by stone bridges. Fortified islands could be added to the moat, adding another layer of defence. Water defences, such as moats or natural lakes, had the benefit of dictating the enemy's approach to the castle. The site of the 13th-century Caerphilly Castle in Wales covers over 30 acres (12 ha) and the water defences, created by flooding the valley to the south of the castle, are some of the largest in Western Europe.
• Gatehouse
The entrance was often the weakest part in a circuit of defences. To overcome this, the gatehouse was developed, allowing those inside the castle to control the flow of traffic. In earth and timber castles, the gateway was usually the first feature to be rebuilt in stone. The front of the gateway was a blind spot and to overcome this, projecting towers were added on each side of the gate in a style similar to that developed by the Romans. The gatehouse contained a series of defences to make a direct assault more difficult than battering down a simple gate. Typically, there were one or more portcullises – a wooden grille reinforced with metal to block a passage – and arrowslits to allow defenders to harry the enemy. The passage through the gatehouse was lengthened to increase the amount of time an assailant had to spend under fire and unable to retaliate in a confined space. It is a popular myth that so-called murder-holes – openings in the ceiling of the gateway passage – were used to pour boiling oil or molten lead on attackers; the price of oil and lead and the distance of the gatehouse from fires meant that this was completely impractical. They were most likely used like machicolations, to drop objects on attackers, or to allow water to be poured on fires to extinguish them. Provision was made in the upper storey of the gatehouse for accommodation so the gate was never left undefended, although this arrangement later evolved to become more comfortable at the expense of defence.
During the 13th and 14th centuries the barbican was developed. This consisted of a rampart, ditch and possibly a tower, in front of the gatehouse which could be used to further protect the entrance. The purpose of a barbican was not just to provide another line of defence but also to dictate the only approach to the gate.