A hillfort is a type of earthwork used as a fortified refuge or defended settlement, located to exploit a rise in elevation for defensive advantage. They are typically European and of the Bronze Age or Iron Age. Some were used in the post-Roman period. The fortification usually follows the contours of a hill and consists of one or more lines of earthworks, with stockades or defensive walls, and external ditches.
Celtic hillforts
Celtic hillforts developed in the Late Bronze and Early Iron Age, roughly the start of the first millennium BC, and were used in many Celtic areas of central and western Europe until the Roman conquest. They are most common during later periods: Urnfield culture and Atlantic Bronze Age (c. 1300 BC – 750 BC) Bronze Age Hallstatt culture (c. 1200 BC – 500 BC) late Bronze Age to early Iron Age La Tène culture (c. 600 BC – 50 AD) late Iron Age
Prehistoric Europe saw a growing population. It has been estimated that in about 5000 BC during the Neolithic between 2 million and 5 million lived in Europe; in the Late Iron Age it had an estimated population of around 15 to 30 million. Outside Greece and Italy, which were more densely populated, the vast majority of settlements in the Iron Age were small, with perhaps no more than 50 inhabitants. Hillforts were the exception, and were the home of up to 1,000 people. With the emergence of oppida in the Late Iron Age, settlements could reach as large as 10,000 inhabitants. As the population increased so did the complexity of prehistoric societies. Around 1100 BC hillforts emerged and in the following centuries spread through Europe. They served a range of purposes and were variously tribal centres, defended places, foci of ritual activity, and places of production.
During the Hallstatt C period, hillforts became the dominant settlement type in the west of Hungary. Julius Caesar described the large late Iron Age hillforts he encountered during his campaigns in Gaul as oppida. By this time the larger ones had become more like cities than fortresses and many were assimilated as Roman towns.
Hillforts were frequently occupied by conquering armies, but on other occasions the forts were destroyed, the local people forcibly evicted, and the forts left derelict. For example, Solsbury Hill was sacked and deserted during the Belgic invasions of southern Britain in the 1st century BC. Abandoned forts were sometimes reoccupied and refortified under renewed threat of foreign invasion, such as the Dukes' Wars in Lithuania, and the successive invasions of Britain by Romans, Saxons and Vikings.
Central Europe
The Hallstatt culture and La Tène culture originated in what is now southern Germany, Switzerland, Austria, Slovakia and the Czech Republic. However, hillforts were built also in Poland and further east, until the Middle Ages.
The predominant form of rampart construction is pfostenschlitzmauer, or Kelheim-style.
Great Britain
The reason for the emergence of hillforts in Britain, and their purpose, has been a subject of debate. It has been argued that they could have been military sites constructed in response to invasion from continental Europe, sites built by invaders, or a military reaction to social tensions caused by an increasing population and consequent pressure on agriculture. The dominant view, since the 1960s, has been that the increasing use of iron led to social changes in Britain. Deposits of iron ore were located in different places to the tin and copper ore necessary to make bronze and, as a result, trading patterns shifted and the old elites lost their economic and social status. Power passed into the hands of a new group of people. Archaeologist Barry Cunliffe believes that population increase still played a role and has stated "[the forts] provided defensive possibilities for the community at those times when the stress [of an increasing population] burst out into open warfare. But I wouldn't see them as having been built because there was a state of war. They would be functional as defensive strongholds when there were tensions and undoubtedly some of them were attacked and destroyed, but this was not the only, or even the most significant, factor in their construction".
