The island received its name for several internationally renowned museums that are now occupying all of the island's northern half (originally a residential area dedicated to "art and science" by King Frederick William IV of Prussia in 1841). Constructed under several Prussian kings, their collections of art and archeology were turned into a public foundation after 1918, the Stiftung Preußischer Kulturbesitz, which maintains the collections and museums today.
The Prussian collections became separated during the Cold War with the entire city, but were finally reunited after German reunification.
Presently, the Museumsinsel and the collections are in the process of being reorganized. Since several buildings were destroyed in World War II and some of the exhibition space is in the process of being reconstructed, the information below is in a state of flux.
The Old Museum (Altes Museum) is the oldest of the museums, finished in 1830 according to the plans by Prussian architect Karl Friedrich Schinkel[?]. It was erected opposite of the (no longer existing) Berlin Castle[?]. The oldest museum building in Berlin, it was here where Frederick William III first made the Antikensammlung, the Prussian collection of antiques, available to the public. This collection is now in part exhibited in the Old Museum again.
The New Museum (Neues Museum), located behind the Old Museum, was completed in 1859 according to plans by August Stüler[?], a student of Schinkel. It was nearly destroyed in World War II (only some of the outer walls remained) and is presently being reerected. According to plan, after the completion in 2009, it shall -- as before the war -- expose the collections of Egyptian and pre-history.
The Old National Gallery (Alte Nationalgalerie) was completed in 1876, also according to designs by August Stüler[?], to host a collection of 19th century art donated by banker Joachim H. W. Wagener[?]. The collection was greatly expanded and is today one of the largest collections 19th century sculptures and paintings in Germany. The building was badly damaged in World War II and only completely restored and reopened in 2001; today, it hosts the paintings of the collections (while the sculptures are located off the island in the Friedrichswerdersche Kirche, a former church).
The last of the museums is the Pergamon Museum, completed in 1930, which hosts original-size, reconstructed monumental buildings such as the Pergamon Altar and the market gate of Miletus, consisting of parts taken from the original excavation sites.
The collections that were united on Museum Island for the first time allowed a unified look at European art from the Antiques up to the 19th century, presented in buildings that display the history of museums in themselves over a course of a hundred years, which is why the entire ensemble was added to the UNESCO list of World Heritage Sites in 1999.