Pheasant Island (or Peace Island, or Conference Island) is the world's smallest condominium. A condominium is a place that has two rulers. The island lies on the French-Spanish border in the Bidasoa River. Since the 15th century, the small island lent itself to diplomatic meetings between France and Spain. Since the Treaty of the Pyrenees was signed in 1659 the island was under joint sovereignty of both countries. Shortly after the Treaty of the Pyrenees was signed, Sébastien de Pontault de Beaulieu (ca. 1612-1674) published a map of the island in commemoration of the peace treaty. The island is uninhabited and access is forbidden, even though it can sometimes be reached on foot from the Spanish side at low tide. It is made of a pile of alluvium that the river would have eroded long ago if it had not been surrounded by a fence. Ironically, there are no pheasants on the island.