The Esterházy treasury was created during the Turkish wars of the Middle Ages, and was added to over the centuries. Towards the end of World War II, the art treasures were transported to the Esterházy Palace in Buda Castle, but the building was hit by a bomb and part of the collection was destroyed or seriously damaged.
That was when the remaining artefacts were transferred to the Museum of Applied Arts. The exhibition now open now presents a selection of ornaments that were severely damaged, partially destroyed or broken into small pieces, before being pieced together by expert restorers. More details here.