In the Moche social world discussed in Chapter 4, warfare and abundant war-related display exaggerated sociopolitical hierarchies and distinguished the special roles of elites as warrior lords and performers of violence. We now jump a few centuries later to the Late Intermediate Period (LIP, 1000–1450 CE) in the southern Andean highlands, when warfare was exceptionally threatening and pervasive, elevating cranial injury rates and driving defensive settlement patterns in many parts of the highlands. This period serves to highlight a different face of war: collective defense and aggression as a medium through which group identities are defined, common territories claimed, and cohesion cemented. These are processes that discourage individuation and elide internal divisions, rather than accentuating them in war. Shared experiences of threat and aggression are a crucible for social solidarity. This tendency is always present in warfare, and may be drawn on strategically to mobilize people in the name of a political, religious, or ethnic “imagined community.” But it is especially important when the stakes are high – the dangers and the potential rewards of war – and when these stakes are shared throughout society. In these cases, group members all benefit from victory and all suffer gravely from loss.