The Bronze Age ( 1800 - 600 BC ) brought about the the Hillforts of England, the biggest being Maiden Castle. The Iron Age and the Romans ( 600 BC - 400 AD ) saw the development of more hillforts and when the Romans invaded England they produced defensive structures such as the massive Hadrian's Wall and Roman Forts. The Fall of the Roman Empire led to a time in the history of England when the Celts of England were invaded by the Scots, the Welsh, the Saxons and the Vikings. A new National Defence system was established by Alfred the Great by the formation of fortified towns called 'Burhs' (later changed to Burghs then Boroughs).
The Development of Castles in England during the Middle Ages - The development of the Norman castle
The Normans brought castles and feudalism to England during the Middle Ages. The Normans literally brought the castles with them on their invasion fleet! These were pre-built wooden castles, which are illustrated on the Bayeux Tapestry.
William the Conqueror employed a strategy of quickly building a network of wooden Motte and Bailey Castles. Timber Motte and Bailey Castles could not be viewed as permanent castles as the wood built on earth rotted quickly and they could easily be destroyed by fire. The development of castles in the Middle Ages continued when the timber castles were replaced with stone castles. The development of the Norman stone castles gave them a power base.
The Development of Castles in the Middle Ages - Feudalism
The outward mark of feudalism was the castle, where the lord resided and from which he ruled his fief. In its earliest form the castle was simply a wooden blockhouse placed on a mound and surrounded by a stockade - called motte and bailey castles. About the beginning of the twelfth century the nobles began to build in stone, which would better resist fire and the assaults of besiegers. A stone castle consisted at first of a single tower, square or round, with thick walls, few windows, and often with only one room to each story. As engineering skill increased, several towers were built and were then connected by outer and inner walls. The castle thus became a group of fortifications, which might cover a wide area.
The Development of Castles in England during the Middle Ages - Concentric Castles
The next stage of the Development of Castles in England during the Middle Ages occurred during the reign of the Plantagenet
King Edward I (1239–1307). King Edward I employed the services of the best architect and builder of this era of the Middle Ages called Master James of St George who developed a style of fortress called the Concentric castle. A Concentric Castle was "a Castle within a Castle". The concentric castle was effectively lots of buildings, walls, towers and gatehouses in one massive castle complex built within in successive lines of defence. The development of the Concentric Castles in the Middle Ages provided even greater power bases. The development of the concentric castles in the reign of King Edward I led to the conquest of Wales and also provided the opportunity to introduce an element of luxury in the development of castles in the Medieval era of the Middle Ages.
The Development of Castles as Fortresses in the Middle Ages
Defence formed the primary purpose of the castle. Until the
introduction of gunpowder and cannon, the only siege engines
employed were those known in ancient times. They included
machines for hurling heavy stones and iron bolts, battering
rams, and movable towers, from which the besiegers crossed over
to the walls. Such engines could best be used on firm, level
ground. Consequently, a castle would often be erected on a high
cliff or hill, or on an island, or in the center of a swamp. A
castle without such natural defences would be surrounded by a
deep ditch (the moat), usually filled with water. If the
besiegers could not batter down or undermine the massive walls,
they adopted the slower method of a blockade and tried to starve
the garrison into surrendering. But ordinarily a well-built,
well-provisioned castle was impregnable. Behind its frowning
battlements even a petty lord could defy a royal army.