A great-grandfather of Vallée Poussin married into the family of Nicolas Poussin, the leading French artist of the 17th century, and being an artist himself this great-grandfather added the name Poussin to his own name of La Vallée.
Ang isang lolo sa tuhod ng Vallee Poussin kasal sa pamilya ng Nicolas Poussin, ang nangungunang French artist ng ika-17 siglo, at pagiging isang artist kanyang sarili na ito lolo sa tuhod na idinagdag ang mga pangalan Poussin sa kanyang sariling pangalan ng La Vallee.