It is not unlikely that the cartoon of the Virgin and Child with St. Anne in London's National Gallery was made for a commission Leonardo had received from Louis XII in October 1499, soon after the French monarch had entered the city of Milan at the head of his conquering army. I advocate this despite recent efforts to assign the cartoon to a much later period in Leonardo's career.
St. Anne seems to have been as popular with the royal family of France as she was with the Florentines, but for different reasons. The tribute paid her in Florence, as one of those saints who had intervened to defend its citizens' threatened liberty, is matched in France by the fact that Louis XII's consort, of her patron saint. The immediate occasion for the commission may have been the anticipated birth of Louis' first heir, which occurred a few days after the king entered Milan. The painting, for which the cartoon was preparatory, was perhaps to be given as a votive offering to some church in Brittany. (The widespread popularity St. Anne enjoyed in these years throughout Europe is further attested by the fact that Louis' successor, Francois I, specifically requested a painting on this subject when he invited Leonardo to settle in France in 1516.
There are two additional reasons for believing that Louis XII commissioned the cartoon. In the first place, this was the claim made by the late seventeenth-century collector-priest Padre Sebastiano Resta. However, since Resta's repretation for accuracy and even honesty is less than one might hope for, it is prudent that we move on to the second reason. In April 1501, Isabella d'Este of Mantua received a letter from Fra Pietro da Novellara, who had just visited Leonardo in Florence on her behalf. His letter quotes Leonardo to the effect that the artist was painting the Madonna with the Yarnwinder (now lost) for Louis XII's secretary, Robertet - which establishes Leonardo's connection with the French court in Milan - and that he had still to complete an "obligation to His Majesty, the king of France." Fra Pietro does not specify the nature of this obligation, but it may bave been a cartoon on which Leonardo was then working and which Fra Pietro described in a second letter he wrote to Isabella some days later. This cartoon represented a Virgin and Child with St. Anne, but since the description does not quite fir the Burlington House Cartoon, it is my belief that it was intended as an alternative to it. Leonardo had evidently become dissatisfied with his work on the Burlington House Cartoon, loeft it unfinished (as it remains today), and started the cartoon described by Fra Pietro. This interpretation of events is made possible by the fact that the Burlington House Cartoon was definitely in existance in 1502, when the figures of the Virgin and the Child were copied by Fillippino Lippi in a fresco he completed that year in the Strozzi Chapel of S. Maria Novella in Florence.