The marquessa Arconati Visconti, born Marie Peyrat (1840-1923) through numerous donations and bequests to various museums and graduate schools has contributed to the enrichment of public collections, and to the developpement the teaching of history an art history, in Paris, in the country, particularly in Lyon, Toulouse and Angers. Deeply republican, a Dreyfus supporter, and anti-clerical, she kept friendly relationships with a number of protestants. It probably influenced her liberalities, in the literary domain, as well as in the arts. Gabriel Monod (1844-1912), Auguste Molinier (1851-1904) and his brother Émile Molinier (1857-1906), as well as Alfred Morel-Fatio (1850-1924), alumni of “l’École normale supérieure “and “l’École des chartes “, studies directors at “l’École pratique des hautes études“, professors at “l’École des chartes“ and at “l’École du Louvre“, chair holders at the “Collège de France”, belong to the erudition world. Raoul Duseigneur (1844-1916), collector and antique dealer, in memory of whom the marquessa multiplied the donations after his death in 1916, “the close friend” has probably been the marquessa’s companion, sharing in particular her taste for objets d’art collections