Ancient Celtic warfare refers to the historical methods of warfare employed by various Celtic people and tribes from Classical antiquity through the Migration period. Unlike modern military systems, Celtic groups did not have a standardized regular military. Instead, their organization varied depending on clan groupings and social class within each tribe. Endemic warfare was a common and significant aspect of life in Celtic societies. However, the organizational structures of these tribes differed widely. Some had rigid hierarchies with ruling monarchies, while others operated with representational structures resembling republics. Over time, the expansionist policies of the Roman Empire led to the incorporation of many continental Celtic peoples into Roman rule, such as Britain. Resulting in the adoption of Roman culture by Gallic and Brittonic cultures. This let to the rise of hybrid cultures known as Gallo-Roman and Romano-British during Late antiquity. As a consequence, Celtic culture became predominantly confined to Insular Celtic people. While archaeological discoveries offer valuable insights into the material culture of the Celts, determining the precise nature of their ancient combat techniques remains a topic of speculation. Celtic Mythology Celtic mythology is fractured as the mythologies of most of the continental Celtic peoples, such as the Gauls, Galatians and Celtiberians, did not survive the Roman conquests. With only remnants found within Greco-Roman sources and archaeology. Most surviving Celtic mythology belongs to the Insular Celtic peoples who were able to preserve their myths and traditions with oral lore. These were committed to writing in the medieval period by Christian scribes, some time after the pre-Christian era they are supposed to depict. Irish mythology has the largest written body of myths, followed by Welsh mythology. Other surviving examples being Cornish mythology, Breton mythology and Arthurian mythology.