Final answer:
Evidence of violence related to warfare primarily comes from archaeological sites, historical writings, and the analysis of ancient societies. While some societies showed no signs of warfare, others, like those in Mesopotamia and the American Northeast, have left substantial evidence of conflict and organised violence, revealing the importance of war in their cultural development.
Step-by-step explanation:
Most evidence of violence related to warfare comes from archaeological findings, historical documents, excavations of ancient settlements, and analysis of ruins. From early Neolithic Europe's fortified settlements to the complex cities of Mesopotamia with their defense-oriented architecture, evidence has shown that organised violence did occur as societies grew. However, it's important to note that not all urbanised societies engaged in warfare, as seen in the peaceful townships like Caral in Peru and ancient Minoan cities, which displayed no traces of war. Intensive archaeological research in Mesopotamia, such as that done at Uruk and Tell Hamoukar, reveals patterns of warfare through the discovery of large-scale destruction and items indicative of conflict like collapsed walls and clay projectiles. Furthermore, the analysis of societies like the Northeast tribes in North America illustrates a culture of warfare driven by revenge and power, highlighting the intricate interconnection between societal structure and the prevalence of war.
The historical record is augmented by detailed accounts of warfare practices, such as the 'Mourning Wars,' and the implications of territorial and resource competition, which are unearthed through the excavation of city fortifications and the remnants of battle. Thus, while not all forms of civilisation practiced ongoing warfare, it has been a significant factor in the cultural evolution of many regions around the globe.