The splitting up or "selling off" of collections of art, cultural artefacts, knowledge and information happens for many reasons. The most common is financial, either because the cost of housing and maintenance is too great, or the money to be made from whole or partial sale is needed, say for settlement of an estate on the death of the collector. Public and private collections are at risk.
The Treaty of Rome (1957) creating the European Common Market gave each country the right to protect its national treasures. With the new open borders and customs-free market from 1993, which gave no special provisions for works of art, a compromise arrangement was worked out. The 12 governments will substitute their current rules for the export of cultural goods outside the community by granting a "passport" valid throughout the region. Goods will will require a special certificate is they are to be exported beyond the community. This protection covers everything that might possibly be appeal to a collector or a museum, if old or valuable enough. For example, paintings must be at least 50 years old, the work's artist must be dead, and it must be valued at more than $187,500. At the other extreme are archaeological items, bits of dismembered monuments, ancient coins and medals, which need prove no commercial value but must be at least 100 years old. In between lie most other items – books, furniture, ceramics, textiles, model ships, theatrical material and more – which must be valued at more than $62,500 per item and variously be over either 50 or 100 years. In addition, goods must be returned if removed illegally from a member country.
Experts estimate that between 50 and 75% of the EEC/EU's art trade and between 85 and 90% of its antiquities business now takes place in London, a market said to be worth around $5 billion a year. Countries like Italy, Spain and Greece, which have already lost many national treasures to museums in northern Europe and the USA, believe strict domestic legislation is necessary to protect what remains. However, it is argued that excessive controls are counterproductive because they stimulate a black market.