Not until the late 19th century did the name of Halong Bay appear on a French Marine Map. “The Hai Phong News”, a French newspaper of the time, had an article, “Dragon appears on Ha Long Bay”, reporting the following story: In 1898 a sub-lieutenant named Lagredin, captaining the ‘Avalanse’ reported seeing a huge sea snake on Ha Long Bay. This was also witnessed by many of the crews. Thus emerged the European image of the Asian dragon. Whether this appearance of a strange animal looking like a dragon resulted the name of Ha Long Bay is not known (Reference “Quang Ninh: Art and Culture” published in 2002).

There is also a local legend, which has been handed down, relating to the name Ha Long Bay, which tells the following tale:
“Long ago, in the first founding days, the Viet people were attacked by foreign aggressors. The Jade Emperor sent the Mother Dragon and her band of Child Dragons to help the Viet people fight the invaders. While the enemy vessels were launching massive attacks against the mainland, the dragons descended in flocks from the sky. They spat out innumerable pearls which changed into  jade stone islands the moment they touched the water. These islands linked together to form firm citadels that checked the enemy’s advance and smashed their vessels to pieces.

After the invaders were driven out, Mother Dragon and her Child Dragons did not return to Heaven but stayed on earth, right at the place where the battle occurred. The spot where the Mother Dragon landed was Ha Long, and where the Child Dragons came down was Bai Tu Long. The place where their tails violently wagged was called Long Vi, the present-day Tra Co Peninsula with its soft sandy beach stretching many kilometers.”