The complex relationship between the Netherlands and Dutchspeaking Flanders is unusual for not being one between equals; the former a state, the latter a region of federal Belgium with its own government.
But the closeness of the two reflects deep and long national and linguistic ties which have been the cause of friction between the two neighbouring states despite being close political partners in the Benelux alliance.
The tensions have arisen because Flanders has long resented its historically subordinate role in Belgium and harboured strong nationalist movements for separation and union with its neighbour.
In the years since the last war, however, new forms of co-operation have evolved, slowly and piecemeal, on a pragmatic basis, to address specific common problems.
Some of this has been of a traditional intergovernmental kind. Flanders and Dutch ministers, for example, have talked to each other for some time about their common management of shared rivers, taking over most fruitfully a previous dialogue with Belgium that had been uneasy.
But 15 years ago a treaty between Belgium and the Netherlands established a new form of cooperation between Flanders and The Hague in the linguistic field. The Language Union is a supranational body with its own executive powers, secretary-general, staff and budget. The union exercises common control over such things as the spelling of Dutch words, linguistic research and the promotion of both language and literature, and is run by a council of ministers involving the ministers for culture and education from the Flanders government and the Netherlands.
In 1993, with the last round of major constitutional reform of the Belgian state, the regions of Flanders and Wallonia were each, unusually, given the legal power to enact international treaties on matters over which they had legal competence. These include such issues as education, culture, science, and aspects of transport and the economy - and very definitely not military questions.
That made possible a new cultural treaty between Flanders and the Netherlands whose provisions are at present in the process of being implemented. A commission of outstanding public figures, appointed by the two governments, will endeavour to formulate a common policy in education, culture, science and the media.
Unlike the Language Union, however, the commission does not have binding powers and will merely advise both governments.