Casting

Casting consists of pouring molten metal into a mold, where it solidifies into the shape of the mold. The process was well established in the Bronze Age (beginning c 3000 BC), when it was used to form bronze pieces. It is particularly valuable for the economical production of complex shapes, from mass-produced parts to one-of-a-kind items or even large machinery. Three principal techniques of casting were successively developed in prehistoric Europe: one-piece stone molds for flat-faced objects; clay or stone piece molds that could be dismantled and reused; and one-off clay molds for complex shapes made in one piece around a wax or lead pattern (cire perdue). Every metal with a low enough melting point was exploited in early Europe, except iron and steel, was used for casting artifacts.

Metals with a low enough melting point can be melted in a crucible on a simple hearth, and cast in a mould. Copper, bronze, gold and silver were all commonly cast in antiquity. Iron and steel could not be melted by ancient hearths and furnaces. Metal melted over fire absorbs gas resulting from combustion of the fuel. Moulds have to be carefully designed to make sure that bubbles of gas do not spoil the casting. castle. The castle has many different meanings in European history and archaeology. Its most familiar use is to describe a fortified residence, but it is sometimes used to refer to later medieval fortified villages. The evolution of the castle has been well documented by European archaeologists. The first late Carolingian types were possibly modelled on the fortified homesteads of the Slavs, but in the 10th century the manor or principal house was set up on a raised mound within the enclosure. This motte and bailey type was introduced to central and northern France in the Uth century, whereas previously only simple enclosures had existed. The Normans then introduced this type to the British Isles and to Southern Italy, and also built stone keeps within their enclosures, using their experiences in the Crusades to accelerate castle design. Hence later 12th-century castles in France and England comprise large stone walls, intumed gateways modelled on Arabic and Byzantine forts, and massive circular central keeps. Multiple walls with strengthened gateways are an invention of the mid-13th century, and splendid examples are still to be seen at Angers in France or in the Edwardian castles of North Wales. During the 14th century the interior buildings within the walls were formed into rational plans to make these quarters more tolerable to live in for longer periods, while at the same time reinforcing their defensive properties. In the later 14th and 15th centuries the introduction of the cannon effectively undermined the value of castles. Spanish and Italian builders compensated by constructing yet more formidable multiple ramparts, while Rhenish castles were sited on high precipitous positions, out of the range of cannon. Henry VIII of England developed a very low form of castle with multiple bastions to hold cannon which was the forerunner of the bunker used until recent times.