The historical background of most nations in Southeast Asia have encountered with the colonialism. This article discusses the emergence of keroncong, a well-known musical genre as a result of cultural interaction during the colonial era in Indonesia. The history of keroncong began in Tugu village in what is now Jakarta as the capital city of Indonesia. In particular, Tugu village community invented a new musical genre that directly absorbed Iberian influence of Portuguese Moresco, of Moorish origins, and is now known as Krontjong Toegoe. In between the advent of Portuguese explorers in 1513 and the independence of Indonesia in 1945, the Dutch were a colonial power for over three and half centuries since 1619. The Colonial Government supported the development of Krontjong Toegoe in urban Batavia. They also built Tugu church to facilitate the descendants of the Portuguese after converted from Catholicism to the Reformed Church. The social background of the Tugu community reveals their contribution to this ubiquitous genre in Indonesia’s repertoire, which is an important discovery. Because Krontjong Toegoe is extant, it is significant as an example of the continuing evolution of a creative form that combines cultural elements from both East and West.