"In Basque Country, in the middle of the Bidassoa river, the tiny "Konpantzia" (in basque), "�le de l�h�pital" or "�le-des-Faisans" (in french), "Isla de los Faisanes" (in spanish) --pheasant island-- is the smallest condominium in the world: it belongs for six months to France and six months to Spain. It was there that the Pyrenees treaty was signed in 1659 by the very young Louis XIV under the tutelage of Mazarin, and Philippe IV of Spain. This treaty defined the border separating the two kingdoms.
Negotiations were lengthy, particularly over Cerdanya. The border was often the subject of dispute and there were aberrations such as Ll�via, the Spanish enclave in Cerdanya. Two centuries past before three Border Treaties were signed (1853, 1862, 1866), defining a border that was generally accepted in the following years. 602 numbered milestones marked the definitive border between the Atlantic and the Mediterranean"