The Wallace Collection is a museum in London occupying Hertford House in Manchester Square, the former townhouse of the Seymour family, Marquesses of Hertford. It is named after Sir Richard Wallace, who built the extensive collection, along with the Marquesses of Hertford, in the 18th and 19th centuries. The collection features fine and decorative arts from the 15th to the 19th centuries with important holdings of French 18th-century paintings, furniture, arms and armour, porcelain and Old Master paintings arranged into 25 galleries.
 
Interesting facts...
the Wallace Collection is essentially a frozen aristocratic time capsule: Lady Wallace’s bequest required it to be kept “unmixed with other works of art,” so the museum cannot simply keep acquiring new objects in the normal way. That’s why it still feels like a private 19th-century house collection rather than a constantly changing gallery.