Introduced in the 16th century by Portuguese, Spanish, and Dominican missionaries, the Catholic Church experienced significant growth in the 17th century, driven in part by Jesuit missionary activity, among which Alexandre de Rhodes emerged as a particularly influential figure.De Rhodes contributed to the creation of the romanized Vietnamese alphabet (chu Quoc ngu), which replaced traditional Chinese characters and Vietnamese-developed characters that were in use before this time.
Despite periods of tolerance, the Catholic faith was subjected to severe persecutions, especially between the 18th and 19th centuries under the Nguyen dynasty, leading to the martyrdom of tens of thousands of faithful: between 130,000 and 300,000 Catholics lost their lives, and 117 of them were canonized as Vietnamese martyrs by John Paul II in 1988.
