Society
The third century BCE is the golden age of the Celts, who then dominated an area comparable to any empire in history. However, they never set up a centralized imperial state, but preferred smaller units each having the liberty to handle their business as they pleased. In critical situations, such as invasions by Romans or other scoundrels, they sometimes took common initiatives, but even then, the cooperation was not frictionless. The Celtic political system changed from time to time and from place to place, but basically, the society was divided in tribes, or peoples, or states, who occasionally split up and sent out offshots to settle somewhere else. Thus, there were Briganti both in England, Spain and Switzerland, Boii in Czechia and Italy, Tectosages in France, Italy and Turkey. Each of the tribes controlled an area of some 5000 square kilometres on the average. Probably, they split up because of overpopulation, they seem to rarely consist of more than a hundred thousand individuals, which seems to have been regarded as a suitable size. Such a state would usually be governed by a king (rix) or occasionally a queen, supported by a senate or council of elders chosen from the various families of the tribe. However, in historic time, some Gaulish states were not ruled by kings, but by annually elected assemblies of so-called vergobrets, possibly with the Roman republic as a model. Elsewhere, the senate ruled alone, but chose a warlord as sole ruler in times of need. The Galatian kingdom in Minor Asia was ruled by a king with an interesting political system known from Greek writers. The senate was elected from each of the different clans in the country. The Galatian kingdom was divided in four pagi or tribes, each governed by a chieftain with two assistant chieftains and a druid with a council of elders. Membership in councils consisting of representatives from the various families or clans probably were for life, and probably, the eldest member of each family automatically took seats in them. Written history gives us a few examples of high officials losing their positions, however, often due to political fraction strifes.
Somewhat apart from this political system stood druids, bards and apparently also other artisans, who could wander between the different states to where their services were at any time the most needed and appreciated, as if they didn't belong to any particular state at all, although druids occasionally were elected to kingship. This was useful, for there was often a high degree of suspicion or hostility between the states. Nations that were hunting for new land didn't mind going for Celtic territory as for foreign lands, particularly in later times, when the Roman territory was so strongly defended and the German pressure from the north was increasing. This could usually not be resolved without conflict, and conflicts between Celtic states were not a rarity. Because of this, the Celts evolved a system for diplomacy, with embassies sent to other states to discuss matters of conflict. Those ambassadors had diplomatic immunity, it was a crime to harm them. Romans and others who didn't have such customs occasionally broke these rules, but they proved so useful in a hostile world that the Romans adopted them and even borrowed the words ambassador and embassy, which we have inherited.
It is difficult to form any opinion as to the situation of the commoners in all this. The descriptions in various sources are scant, and range from slavery to a kind of communism where everything was common property. Possibly, the Celtic society was ruled by a warrior aristocracy on whom the propertyless were totally dependent. Such societies are found in many places and times. But in more modern times, Celtic clans have been known to practise a high degree of brotherhood and property-sharing. From the recounts of the wanderings of the Helvetii, it is said that they numbered 400000 individuals, of which 92000 were under arms, and this is consistent with the whole of the adult male population participating in the defence, if the numbers are correct. From the battles of the Celts with other peoples, I know no instances of bribes causing a Celtic lower class to betray their masters, which happened many times other places. The Romans rather preferred exploiting the rivalry between the different states, bribing those that were in opposition to the most powerful ones. Many political offices in Celtic societies were elected, but it is not known who the electors were. The central tribal council is an institution where each of the tribes chose 10-20 representatives to assemble one or a few times a year or in occasions of particular need. General assemblies are known, possibly in connection with fairs, where you could raise issues of concern. But it is not known if all had the right to do this or if it was limited.
The Celtic habitation pattern was very scattered from the beginning, with groups initially probably pretty close to the natural family group size of 30 adult individuals. They built round huts with wicker walls and reed roofs, light materials that were quickly set up and provided good shelter, comfort and warmth. Everything was renewable, so they didn't have to kill a thing to make a home for themselves. In cross-section, these houses had a c-shape, an open circle, evidently a symbol with very deep significance for them. These habitations were scattered about, often over wide areas. For protection against enemies, they built hill forts on nearby hilltops (oppida) where the population could seek refuge. In the last centuries of independence, some of the hill forts of southern Litavia (France) developed into real towns with a more permanent habitation, and in Galatia and seemingly in Thrace, they moved into existing towns to some extent. But this is a late development, and during most of the richest cultural flowering, they upheld an advanced civilization just about totally without towns. Which proves that it is possible after all.