The Louvre grew in reputation and fame in the 19th century. Many of the great painters of the Impressionist movement spent time studying and practicing at the Louvre, including Edgar Degas, who was licensed to create copies of the museum's paintings. Leaders of the Impressionist movement grew in popularity elsewhere in Europe, although the Louvre's governors largely ignored them until the 20th century, when the museum began acquiring and accepting donations of Impressionist works.
The pieces by the Impressionists and other movements of the late 19th and early 20th centuries would hang in the Louvre only until 1986, when the Musée d'Orsay opened across the River Seine. The Louvre divided its collection, sending all work created after 1848 to the d'Orsay and maintaining its collections of Renaissance, Hellenic, Egyptian, Asian, and Roman art and antiquities. Eventually these collections would be expanded to include cultural artifacts from indigenous peoples from the Americas and Oceania as well.
The Louvre suffered two major strains during the modern era. In 1871, the Paris Commune, a revived socialist group seeking to protect the rights of workers, revolted and turned its ire against the Palais des Tuileries, which had long served as residence for the monarchy. The palace burned completely, along with its contents.
World War II posed another challenge to the museum's directors. As the Nazi armies invaded Paris, the Louvre was emptied of its contents, except for the heaviest pieces. The Louvre's collections were secretly distributed among wealthy French citizens, who hid pieces in their châteaux around the country. Eventually, the Louvre reopened under Nazi occupation. It served as a clearing center for art looted by the Nazis, called the Louvre sequestration, both from conquered territories and from the collections of Jews and other groups executed by the Nazi war machine [source: The Louvre].
The Louvre closed from 1945 to 1947 following the liberation of France. Once again, it entered a period of revitalization. In 1989, the glass pyramid entrance designed by Chinese-American architect I.M. Pei opened to the public. It has become a symbol of the modern Louvre, but trails back to the origins of the building. During excavation for the project, the moat and a keep from the first medieval incarnation of the building was uncovered and is preserved for display for visitors today.