In 1853, he acquired the Château Brane Mouton, a vineyard in Pauillac in the Gironde département from a Paris banker named Thuret who had previously bought it from Baron Hector de Branne in 1830.

A prestigious first growth (premier cru) property more than three times the size of Chateau Mouton, it created a family rivalry.

They had the following children: In 1856, Nathaniel and his wife purchased the property at 33 Rue du Faubourg Saint-Honoré in Paris from Denis, duc Decrès.

He and his wife undertook extensive restoration work and new construction to turn the lakeside property into a luxurious country home.

It would be 118 years later before Château Mouton, under the leadership of Nat's great-grandson Philippe de Rothschild (1902–88), would become the only French vineyard to ever achieve reclassification to First Growth.