Chapter 3 examines mythical, historical, and scientific facts. It offers a brief history of East Asian international relations, paying particular attention to the Chinese World Order, the Khmer Empire, and post-colonial Filipino historiography as samples for how to theorize histories from an IR perspective. The chapter discusses war and peace as well as political economy, the subject matters important for East Asian history and IR theory. It also offers a section on impacts and lessons of history, illustrating how history contributes to background knowledge, historiography and belief systems, foreign policy analysis, and IR theory. A better understanding of East Asian history allows us to contextualize contemporary issues without which we may not be able to put together a puzzle. Historical experiences inform our belief system, into which people typically fit new events or factors as explanation. History is evolutionary by nature, whether we frame it that way explicitly or not.