Humans have always had the desire to protect themselves, the early humans often sought protection in caves; they lit a fire near the entrance to avoid wild animals from coming in and the single opening ensured that a threat could only come from one side.
In contrast to what many people think, most early humans did not really live in caves, they mostly used them for protection, gatherings, and probably for religious purposes; the most common form of habitation in that time were huts and tents made of straw or animal hides.
This early villages were vulnerable to attacks from dangerous animals like bears and wolves and of course the most dangerous of them all; other humans, who are always willing to kill their own kind.
To protect themselves from this threats the early humans positioned their houses on high grounds that were easier to defend, the old Germanic word for "city" is "burg", a word that also means "stronghold" and may also link to "berg", which means mountain.
It didn't take long before hill-fortresses were constructed; people looked for well-defendable sites like flat mountains or hills surrounded by fertile lands that could be used for farming and settled there, in this "fortresses" civilization began to flourish and the earliest kingdoms, civilizations, and other forms of controlled society in Europe came into existence there.
Villages were often build next to water, when there was no mountain or hill near the water to found the village on another tactic was sometimes used; the village was build in a loop or fork in the river, this way the village was mostly surrounded by water so that only a small strip of land gave access to it.
Another interesting natural defense is described by Julius Caesar in book 2 of his "Commentarii de bello Gallico": "It added weight also to the advice of those who reported that circumstance, that the Nervii, from early times, because they were weak in cavalry, (for not even at this time do they attend to it, but accomplish by their infantry whatever they can,) in order that they might the more easily obstruct the cavalry of their neighbors if they came upon them for the purpose of plundering, having cut young trees, and bent them, by means of their numerous branches extending on to the sides, and the quick-briars and thorns springing up between them, had made these hedges present a fortification like a wall, through which it was not only impossible to enter, but even to penetrate with the eye. Since therefore the march of our army would be obstructed by these things, the Nervii thought that the advice ought not to be neglected by them."
Terpen and Wierden:
In some areas humans were confronted with a problem; there were no mountains or hills to build their villages on nor were there any rivers or other natural defences, so they began surrounding their villages with artificial defences like wooden palisades and moats or ditches, in some places they even constructed hills of dirt, garbage, rubble, and sand to build their houses on.
In the northern parts of Germany and the Netherlands (especially the Frisian lands) the people constructed "terpen" and "wierden", which were small artificial hills on which individual houses and farms were built, this was not only done for defensive purposes; the Netherlands is a very flat area that often flooded (and still floods if we wouldn't have those magnificent dikes) so people also lived on hills to keep their feet dry in the case of a flood.
The oldest terpen were 3 meters (9.8 feet) high but later there were also ones of 6 meters (19.7 feet), around the terp was a ring-road (also called "oxes-road") that gave access to the doors of the stables that were also built in a circle, the tiny streets lay in a radial position towards the center of the hill, on this center was often a courtplace that was called "Feit" or "Frijthof", in later times churches were often built on this Frijthoven.
The terpen and wierden are mentioned by Plinius (Pliny) the Elder in his Naturalis Historiae Liber XVI.2-3 where he uses them to make fun of the Frisians: "There, twice in every twenty-four hours, the ocean's vast tide sweeps in a flood over a large stretch of land and hides Nature's everlasting controversy about whether this region belongs to the land or to the sea.
There these wretched peoples occupy high ground, or manmade platforms constructed above the level of the highest tide they experience; they live in huts built on the site so chosen and are like sailors in ships when the waters cover the surrounding land, but when the tide has receded they are like shipwrecked victims. Around their huts they catch fish as they try to escape with the ebbing tide. It does not fall to their lot to keep herds and live on milk, like neighboring tribes, nor even to fight with wild animals, since all undergrowth has been pushed far back."
The Oppidum:
During the Bronze Age the Celts created large round hill fortresses on which they often built entire villages; they adapted existing hills by levelling the tops and making the slopes steeper, extra defences were added in the form of wooden palisades and moats, the Romans named this fortress type "oppidum" (plural="oppida"), several interesting examples of this oppida still survive today.
When the Germans began conquering the Celtic lands they also took control of the oppida that they then used for their own purposes, they must have thought; "why build one when you can take one?"
The Germans were a very mobile people so they didn't really need big fortresses, stone was also scarce in most parts of northern Europe so fortifications were mostly made of wood.
Although the oppidum is considered a typically Celtic type of fortress most other peoples in Europe also constructed similar types, hill fortresses were common in Europe and although most of them were built by the Celts there were also many other peoples who created them; the Germans and Slavs are also known to have built hill fortressess.
One of the most famous oppida is the one at Alesia (nowadays Alise-Sainte-Reine in France) where the Romans under Julius Caesar defeated the Celts under Vercingetorix.
Lîmes:
Although the Lîmes were built by the Romans and not by the Germans they are still interesting enough to mention here, during the Roman occupation of Europe new types of fortifications were introduced; the Lîmes, this were long defensive walls that the Romans used to defend their borders against invading Germanic tribes, a bit like the Great Wall of China only then on a smaller scale.
This defensive lines consisted of moats, pallisades, walls, and ditches, garrison towers were placed along the lines within sight of eachother and bigger fortresses were placed within a few days marching distance of eachother; however, this was only theoretically, in practice the defensive line was full of gaps and in most places the border could be crossed without any notice, in later periods the Roman Empire couldn't even afford manning all the fortresses along the line.
In the beginning the Roman fortresses proved effective against Germanic invasions because Germanic armies were not very skilled in siege tactics since they lacked proper equipment like ballistae and catapults, in later periods the Germans seem to have learned how to conquer enemy fortresses because archeologists have found lots of fortress foundations along the old borders that were completely burned to the ground.
The Walburg:
A typical Germanic fortification was the "walburg", a small village surrounded by a "wal", which did not only mean "fall" or "fallen", but also "fence" or "fortification", the modern English word "wall" originates from it.
This "wal" was made of heightened earth and wooden palisades were placed on top of it, when there was water nearby a moat was dug around it, walburgen were commonly used by the Germans, especially in northern Germany and the Netherlands.
Below you can see a good example of what a walburg would have looked like, it is a reconstruction of the "Hunneschans", which was a Saxon walburg from the 9th century AD near the Dutch town of Uddel.
The Landweer:
Landweren were already created in the Bronze Age and probably even earlier, in later periods the landweren became increasingly important in defending farms and villages.
Owners of a farm or a group of farms used to create a "landweer" at the border of their farmland, A well fortified landweer ("land-defence" or "land-block") consisted of a broad ditch filled with water and a heavy wooden fence ("holtwal"), the entrance roads that crossed the landweer were blocked by levers, a smaller landweer only consisted of an earth wall with sometimes a hedge.
Gotenburgen:
The Goths in the Crimea carved houses into the stone cliffs of mountains and rocks, this city-fortressess were called Gotenburgen (Gothic-strongholds) and served as well-defendable cities from which the surrounding lands could be controlled, the mighty Gothic capital Dori was also a Gotenburg.
Several examples of Gotenburgen still exist today in the Ukraine and especially in the Crimea but unfortunately if is difficult to find information about the Gotenburgen and pictures of them are even more exceptional, fortunately I have managed to obtain a picture that you can see to the right.
Danevirke:
The Danevirke ("Dane-works") were defensive lines of earth walls in southern Sleswig that were constructed by the Danish king Godfried in 808AD to defend his country against Charlemagne, despite this defences Denmark fell to the Franconians anyway and was Christianized.
In the 19th century the Danes also used the Danevirke as a defensive line to keep the Prussians out of Sleswig.
Viking fortressess:
A later type of fortress is the temporary Viking camp; when the Vikings invaded a country and decided to stay a little longer they often built a temporary fortification that looked much like a walburg; they created an earth wall and surrounded it with a ditch or moat, within their new fortress they built some wooden huts.
The Vikings also built bigger permanent versions of this type which have mainly been found in Scandinavia, the smaller temporary ones have also been found throughout mainland Europe.
Herbergen:
Armies on the move often constructed temporary strongholds to spend the night or to await further orders, during the early Middle Ages this type of stronghold was called "Herberg", which can be translated as "Army-fortification".
The Herberg was not a real fortress but rather a crude and often temporarily defensive position that was sometimes fortified with palisades and ditches, the herberg also became a safe haven for travellers who wanted to spend the night without risking attacks from wild animals and bandits, they often had to pay for their stay at the herberg and soon beds, food, beer, and other services were offered at the herberg too, after some time the herberg changed into a tavern or inn, and in Germany and the Netherlands the word "herberg" is still used for an inn.
Medieval fortressess:
During the early Middle Ages the use of fortresses became more frequent, the new feudal society divided Europe into a patchwork of tiny states that all had a leading Earl, Count, Duke, or other noble.
Most of this small states were a part of a bigger kingdom but the influence of the kings did not often reach further than their own palaces, the nobles in their tiny states constantly waged war upon eachother and tried to take eachothers houses to kidnap the other noble for ransom, this forced many nobles to reinforce their houses.
They started with erecting palisades and digging a moat around their house but when siege tactics began to improve they also had to improve their strongholds; a residential tower was created with high placed windows which was better defendable, the noble lived in this tower with his family which was very cold and unhealthy, when siege tactics improved again the nobles were also forced to improve their towers which eventually lead to the birth of a new type of fortress; the castle.
One of the first castle types was the Motte-castle; the sand from the moat was used to create an earth ringwall like in the Germanic walburg, this was often combined with a residential tower in which the noble could retreat when the enemy broke through the first defences, this tactic was also applied in most later castles where one of the towers was made bigger and stronger than the rest so that it could be used as a last refugee when the walls were breached, this "last resort tower" was called "donjon", which is a French loan word.
The name "castle" is derived from Latin "castellum", which was a type of fortress the Romans used to house their soldiers in, in most of our modern movies a castle siege is depicted as an enormous event with hundreds of soldiers trying to take a castle but in reality most castle sieges were small battles between only a few men, a battle in which more than 30 soldiers took part was already considered big.
Some spectacular castles have survived in Europe, especially in France, Spain, Germany, Ireland, Scotland, and Great Britain, after the introduction of the cannon in siege warfare the role of the castle was over, most castles have later been transferred into luxurious residences by the nobles and in most castles a part of the wall was broken down to get more sunlight into the inner courtyard.
Motte-castle
During the early Middle Ages the Visigoths occupied southwestern France where they constructed a stronghold that they named Æreda, the French later extended the castle and renamed it into Carcassonne, this beautiful castle still stands today and gives an interesting image of Medieval architecture.
In some areas humans were confronted with a problem; there were no mountains or hills to build their villages on nor were there any rivers or other natural defences, so they began surrounding their villages with artificial defences like wooden palisades and moats or ditches, in some places they even constructed hills of dirt, garbage, rubble, and sand to build their houses on.
During the Bronze Age the Celts created large round hill fortresses on which they often built entire villages; they adapted existing hills by levelling the tops and making the slopes steeper, extra defences were added in the form of wooden palisades and moats, the Romans named this fortress type "oppidum" (plural="oppida"), several interesting examples of this oppida still survive today.
Gotenburgen:
During the early Middle Ages the use of fortresses became more frequent, the new feudal society divided Europe into a patchwork of tiny states that all had a leading Earl, Count, Duke, or other noble.
