In northern Vietnam (Đàng Ngoài–outer realm), the Lê Emperors barely sat on the throne while the Trịnh lords held power of the court. The Mạc controlled northeast Vietnam. The Nguyễn lords ruled the southern polity of Đàng Trong (inner realm). Thousands of ethnic Vietnamese migrated south, settled on the old Cham lands. European missionaries and traders from the sixteenth century brought new religion, ideas and crops to the Vietnamese (Annamese). By 1639, there were 82,500 Catholic converts throughout Vietnam. In 1651, Alexandre de Rhodes published a 300-pages catechism in Latin and romanized-Vietnamese (chữ Quốc Ngữ) or the Vietnamese alphabet. The Vietnamese Fragmentation period ended in 1802 as Emperor Gia Long, who was aided by French mercenaries defeated the Tay Son kingdoms and reunited Vietnam. Through assimilation and brutal subjugation in the 1830s by Minh Mang, a large chunk of indigenous Cham had been assimilated into Vietnamese. By 1847, the Vietnamese state under Emperor Thiệu Trị, people that identified them as "người Việt Nam" accounted for nearly 80 percent of the country's population. This demographic model continues to persist through the French Indochina, Japanese occupation and modern day. Between 1862 and 1867, the southern third of the country became the French colony of Cochinchina. By 1884, the entire country had come under French rule, with the central and northern parts of Vietnam separated into the two protectorates of Annam and Tonkin. The three Vietnamese entities were formally integrated into the union of French Indochina in 1887. The French administration imposed significant political and cultural changes on Vietnamese society. A Western-style system of modern education introduced new humanist values into Vietnam. Despite having a long recorded history of the Vietnamese language and people, the identification and distinction of 'ethnic Vietnamese' or ethnic Kinh, as well as other ethnic groups in Vietnam, were only begun by colonial administration in the late 19th and early 20th century. Following colonial government's efforts of ethnic classificating, nationalism, especially ethnonationalism and eugenic Social Darwinism were encouraged among the new Vietnamese intelligentsias discourse. Ethnic tensions sparked by Vietnamese ethnonationalism peaked during the late 1940s at the beginning phase of the First Indochina War (1946–1954), which resulted in violences between Khmer and Vietnamese in the Mekong Delta. Further North Vietnam's Soviet-style social integrational and ethnic classification, tried to build an image of Diversity under the harmony of Socialism, promoting the idea of the Vietnamese nation as a 'great single