This article analyzes the role the transnational and colonial legacies in Siamese collecting practices in the nineteenth century and twentieth century. Through the case study of a Ganesha statue (Phra Phi Ganet) from Candi Singosari near Malang, East-Java, in the Bangkok National Museum (Phiphitthaphanthasathan Haeng Chat Phra Nakhon), this article argues that king Chulalongkorn, on his second trip to Java in 1896, was an active actor who was able to benefit from the Dutch lack of professionalisation in Javanese collecting practices to gather a large amount of objects, which he utilised to foster the creation of Thai national modernity and identity. As such, it argues we must understand this dynamic not as pure Westernisation but rather a refraction of the colonial model of Java, where Thai national identity was built on objects from outside Siamese borders. Based on the diary of Chulalongkorn as well as Dutch, Indonesian, and Thai archival sources, it shows how Chulalongkorn collected objects of Hindu-Buddhist nature that fitted his interest and legitimacy for royal authority, cemented by 1926. By doing so, this research allows us to reconsider the colonial collecting practices outside the coloniser-colonised dichotomy, the transnational aspect of modern nation-building, and their implications for museums across Southeast Asia and Europe today.