This dissertation explores the maintenance of peace in Pennsylvania during the colonial era. When other colonies along the Atlantic seaboard experienced warfare in the early decades of settlement, Pennsylvania presents an anomaly for experiencing 120 years of relative peace with Indians before becoming a center point for two major conflicts in the latter half of the eighteenth century. The existing scholarly literature has examined the Long Peace and two conflicts, the French and Indian War and the War for American Independence, as distinct periods in the colony's history. When considering these periods through a lens of military violence, scholars point to the lack of military tradition and culture under the Quaker-led government during the Long Peace as an explanation for Pennsylvania's poor military reaction when at war and have used racial, religious, and political interpretations to discuss violence in the colony. In contrast, I argue that the inhabitants of Pennsylvania did have an effective approach for securing the safety of their settlement. I demonstrate that a security culture of restraint developed between Indians and European settlers, marked by dialogue, not war, in the fifty years prior to the formal establishment of Pennsylvania. When they arrived, William Penn and Quaker leaders recognized this understanding to be already in place and they infused into this preexisting structure their own ideals of community and brotherhood of man while continuing the practices of the culture of restraint. I explore how restraint and these Quaker ideals eroded during the eighteenth century, but argue that the culture of restraint ultimately had a lasting legacy through its outward symbols, language, and shared memories assisting in reestablishing peace along the frontier following war. My dissertation thus revises our understanding of Colonial Pennsylvania's long period of peace and how Quakers approached the issue of security in the colony, while also demonstrating the value in considering the role of peace in military history and security affairs.