There is little surviving evidence of Welsh military texts. Outside the formularised heroic literature, descriptions of battles, tactics and army compositions are rare. The main literary sources are:
There are also brief mentions in the pre-twelfth century 'Lives' of four saints: Cadog, Illtud, David, and Samson.
Overwhelmingly the evidence speaks of the king and his mounted war-band who were drawn from the nobility. There may be a bias against the inclusion of the peasantry in the records of some of the larger battles, but for the average raid this was clearly all that was needed. Some of the more powerful nobles may also have had their own war-band. Warriors could fight on horseback or on foot. The spear was the principle weapon, but nobles are recorded as owning a sword and wearing a mail shirt - presumably kings did so too if they wished to be kings for any length of time. The round shield and knife were also standard equipment. There are no descriptions of armed peasants in the literature. However, as they could certainly be called upon for military service we may assume they would have armed themselves with the crudest of weapons: spear and shield, knife, wood axe, bow or some agricultural implement. Peasants would probably have travelled and fought on foot if they ever found themselves in such a position.
Of greater use to the Welsh kings of the tenth and eleventh centuries was the supply of Viking and Saxon mercenaries. The Viking mercenaries were probably drawn from Dublin and paid in silver in the form of coin or hack-silver, for there were no major Scandinavian settlements in Wales. Archaeological and documentary evidence seems to suggest that the Vikings concentrated almost exclusively on the lower lying coastal areas. The vast majority of raids were seaborne and most were aimed at Anglesey or Dyfed. Settlement probably only occurred on a relatively large scale in Dyfed, if the place name evidence is to be accepted. Many other scattered sites around Wales suggest that the Vikings had a direct effect on the coastal fringe of Wales. This is indicating to us more and more that they did the same as they had done before in other areas and created small settlements and farms in the flatter coastal edges. Anglesey, from the Norse Onglsae, or Ongul's sea, has been the site of some intense archaeological interest of late regarding the siting of Viking dwellings. These sites often occur close to previous sites used by the Welsh, and far from pushing them out, it seems that a gradual integration took place. The archaeological evidence is mostly limited to chance finds along the coastline, so that possible settlement site on the isle of Grassholm is no longer a solitary site. Swansea comes from Swein's sea, and Orm's Head near Llandudno speaks for itself. So who were the Vikings raiding around the Welsh coast, the Welsh or themselves?
The English also allowed themselves to be used as mercenaries, playing off one Welsh king against another, and occasionally employing the Welsh in their own campaigns. It is clear that the availability of mercenaries in eleventh century Wales promoted warfare on a greater scale than was usual before.
The archaeological evidence for weapons is virtually non-existent, due to the lack of excavated early medieval sites. The Welsh were Christians and did not normally bury weapons with their dead. There are a few spearheads of non Anglo-Saxon type that cannot be dated to the Iron Age or Roman periods. There is also a very fine silver sword hilt decorated in an Anglo-Saxon style from Radnorshire, now on display in the British Museum. There are no depictions of fighting men on surviving stone sculptures, likewise the very few early Welsh manuscripts that survive do not depict fighting men.
The crux of this subject is that the Welsh have enjoyed just as many other cultures have done, talking about their past victories. But how long ago they all were is anyones guess. The Vikings say little regarding Welsh resistance. And their arch rivals the English, according to the Anglo-Saxon Chronicles only suffered one major defeat in 1055 when their horse borne foray to teach the Welsh a lesson went belly up. This it has to be said was redressed by a more traditional attack a little later. Post Offa's Dyke, which runs down the border of Wales and England, the Welsh were regarded as a nuisance if they did venture into English territory, as opposed to an outright threat that the Vikings posed.
Offa's Dyke, a huge undertaking, and despite the various watch posts and signal beacons, was not impenetrable. The signal fires could have alerted the militias in the various towns and villages within half an hour from coast to coast. The ditch and palisaded dyke would have made it difficult for Welsh raiders to enter England, but almost impossible for them to return laden with any booty such as cattle. Cattle, especially good breeding bulls, were worth their weight in gold, and at least it didn't need carrying, and you could eat the evidence.