Gulangyu, also known as Kulangsu, lies across a narrow strait from Xiamen on China's southeastern coast. Fishing, local settlement, and maritime activity preceded the island's later international prominence. After the First Opium War, Xiamen opened as a treaty port in 1843, bringing foreign merchants, missionaries, and consular representatives into an unequal system imposed through imperial pressure. The island offered a residential setting close to commercial activity but separated from the crowded mainland city. Chinese residents and overseas Chinese families remained central participants in its subsequent development.

In 1903 Gulangyu became an international settlement with a distinct municipal administration. Consulates, churches, schools, hospitals, businesses, and residences developed along winding streets adapted to the island's hills and shoreline. Public services and regulations reflected both foreign influence and local negotiation. The settlement should not be understood simply as a European enclave: Chinese owners, builders, workers, and return migrants shaped much of its architecture and social life. Their investments connected the island with trading and migration networks extending through Southeast Asia and beyond.

Buildings combined regional Chinese traditions with colonial, classical, Gothic, and other architectural references. Verandas, gardens, decorative façades, roofs, and interior arrangements responded to climate, social status, and the tastes of patrons who often knew several cultural worlds. The resulting forms have been described as an Amoy Deco style, reflecting a distinctive local synthesis. Schools and religious institutions contributed to a strong musical culture, and pianos became closely associated with the island. These artistic traditions grew through education, household practice, migration, and institutional exchange rather than from architecture alone.

War and the end of the treaty-port system transformed Gulangyu's political position during the twentieth century. Japanese occupation and subsequent changes of government disrupted residents and institutions. After 1949, buildings acquired new public, residential, and institutional uses, while some former owners and communities left. Later tourism and heritage protection brought renewed attention to the island's architectural character. Restoration, museum development, and commercial adaptation helped preserve important structures, but also changed the balance between ordinary neighborhood life and the needs of large numbers of visitors.

UNESCO inscribed Kulangsu as a Historic International Settlement in 2017. Conservation encompasses buildings, gardens, roads, shorelines, and the relationships among them, with typhoons, humidity, salt, fire, and tourism creating continuing pressures. Maintaining a lived community is as important as preserving attractive façades. Gulangyu is significant because its urban fabric records both the inequalities of the treaty-port era and the creativity of people moving between cultures. The island's houses and institutions reveal how international trade, migration, education, religion, and local craftsmanship produced a distinctive Chinese maritime settlement.