Nathan's credo was expressed in the advice he repeatedly gave his children and grandchildren: "Love France. And go to the Louvre."

Nathan Wildenstein (1851-1934) was born on 8 November 1851 and grew up in Fegersheim, a village in Alsace south of Strasbourg. The Wildenstein clan had resided in Fegersheim since the beginning of the 18th century, and for generations many of them made their living in the buying and selling of horses. Nathan left school at an early age and worked for a time selling men's ties in a shop in Strasbourg run by Wildenstein cousins. He considered himself a Frenchman and against his father's wishes nineteen-year old Nathan had elected to leave his native Alsace after the Franco-Prussian War. However, his departure created a serious rift between him and his family, with whom he had little further contact.

From Strasbourg, Nathan traveled to Paris, which was still under siege so he was turned away and may have worked for a while in Liège. Once he returned to France, he settled in the province of Champagne, where he apparently worked in the shop of a tailor or cloth merchant. He is said to have visited the Château of Vitry-la-Ville belonging to Comte de Riancourt, where he saw among the other paintings a portrait of a woman by Nattier, a work with which he became infatuated and which his gallery would later acquire and sell to John D. Rockefeller, Jr. In Vitry, Nathan met Laure Lévy (1856-1937), the daughter of Samson Levy and Leah Milhaud. Nathan courted her for a number of years and they finally married on March 31, 1886.

Nathan ultimately settled in Paris, where he and a partner named Lachatroulle ran a manufactory of neckwear and cuffs at 111, rue Montmartre, a business that was still operating in 1876. One day, a Countess Potocka with whom he was acquainted asked him to sell an Old Master painting for her, a portrait of a Flemish dignitary by, or at least attributed to, Anthony van Dyck.