Northern Catalonia, North Catalonia, French Catalonia or Roussillon refers to the Catalan-speaking and Catalan-culture territory ceded to France by Spain through the signing of the Treaty of the Pyrenees in 1659 in exchange of France's effective renunciation on the formal protection that it had given to the recently founded Catalan Republic. The area corresponds roughly to the modern French département of the Pyrénées-Orientales which were historically part of Catalonia since the old County of Barcelona, and lasted during the times of the Crown of Aragon and the Principality of Catalonia until they were given to France by Spain. The equivalent term in French, Catalogne Nord, is used nowadays, although less often than the more politically neutral Roussillon (Catalan: Rosselló); Rousillon, though, historically did not comprise Vallespir, Conflent and Cerdagne (Cerdanya). Often the terms Pays Catalan (País Català), "Catalan Country" may be used. Geography Northern Catalonia forms a triangle between the Pyrenees to the south, the Corbières Massif to the north-west and the Mediterranean Sea to the east. The Roussillon plain in the east, by far the most populated area, is formed by the flood plains of the rivers Tech, Têt, and Agly (). The districts of Vallespir and Conflent cover the upper valleys of the Tech and the Têt respectively. The massif of the Canigou (), 2785 m, dominates much of the territory. The climate is of the Mediterranean type, with hot, dry summers and winters which are relatively mild, at least on the Roussillon plain where snow is rare. The city of Perpignan () accounts for over a quarter of the population, over one-third of its urban area is taken into account, and is the only major administrative and service center. Major road and rail links run north–south through Northern Catalonia between France and Spain, while a railway line also links Perpignan to Latour-de-Carol (Catalan: La Tor de Querol) via Prades (Catalan: Prada de Conflent or Prada). Cerdagne Haute-Cerdagne () is geographically distinct from the rest of Northern Catalonia, lying to the south of the Pyrenean watershed in the upper valley of the Segre. It is a mountainous and sparsely-populated district, and includes the town of Llívia (pop. 1252 (2005)) which is an exclave of Spain. The district lies on the most direct route between Toulouse () and Barcelona (via Foix and Ripoll), and a railway line still links the two cities via Latour-de-Carol (). Administrative history Spanish marches