When most people think of Vietnam in a historical context, the Vietnamese war and the American role come to mind, or perhaps the French and their colonization of this Southeast Asian country. However, the very first Europeans to reach (on a verified basis) the kingdoms of Tonquin, Cochinchina and Champá, the constituent parts of today's Vietnam, were the Portuguese.
Portuguese missionaries based in Goa started traveling to Vietnam in the 1500s, and it wasn't until 1660s that the French arrived in significant numbers (conveniently during the Portuguese war of independence against Spain). This set off considerable rivalry between the two European groups, and in 1738 Pope Clement XII ordered that Vietnam be divided into two spheres of influence, with Portuguese missionaries in the north and French missionaries in the south. The French aligned themselves with the nobles of the ascendent Nguyen dynasty, who eventually took control of the northern part of the country and promptly expelled the Portuguese at the request of their French allies.
While the modern Vietnamese language has absorbed considerable vocabulary from the French, its Latin-based script was actually developed by a Portuguese Jesuit by the name of Francisco de Pina. The first European able to speak fluent Vietnamese, de Pina pioneered the method of recording the Vietnamese language with Latin characters, making it easier for other missionaries to learn. At the time, the Vietnamese themselves wrote using classical Chinese, but it was like Latin to the German – highly formal and quite foreign.
The French missionary Alexandre de Rhodes studied under de Pina, and later published in 1651 in Rome the Dictionarium Annamiticum Lusitanum et Latinum, a trilingual dictionary between Vietnamese, Portuguese and Latin that he compiled from the work of various Portuguese Jesuits including Gaspar do Amaral, António Barbosa, António de Fontes and of course Francisco de Pina. For this reason, de Rhodes, and therefore the French, are often credited with developing the latinized script of the Vietnamese language. However, the little-known truth is that what the Vietnamese call chữ Quốc ngữ, or “script of the national language” and an important symbol of Vietnamese identity (especially vis-à-vis the Chinese), was actually a "gift" of the Portuguese.