The early twentieth century was the high tide of Western colonialism, a period of intense manoeuvring between Siam, France and Britain. The heroic diplomacy of Chulalongkorn is the lens through which many Thais recall this era. This chapter considers when and where the idea of a Great Power first emerged, and then explores how it may have arisen or been transferred into a Thai context. It discusses the first site of memory, that of Europe, by unravelling the legacy of Thailand’s brush with colonial France and argues that the personalisation around the figure of Chulalongkorn has enabled it to become what psychologists call an intergenerational trauma and considers the European countries which Thais considered benign, if unreliable, Britain and Russia. The chapter describes the memorialisation of two non-European major powers, India and Japan, which are assuming larger roles in Thai foreign policy in the twenty-first century.