Tributo de las Tres Vacas Historical milestone · Isaba/Izaba, Pirineo, Navarra Image of Isaba/Izaba, not of the place itself. Every 13 July, representatives of the Navarrese Roncal valley and the French Baretous valley meet at the Piedra de San Martín, at 1,721 m altitude on the Ernaz pass, for the Tributo de las Tres Vacas (Tribute of the Three Cows): the mayor of Isaba, as president of the ceremony, asks the Baretous representatives three times whether they will pay the tribute; after their affirmative answer and the "Pax avant" gesture with hands placed on the boundary marker, three cows of Pyrenean breed are handed over, following a veterinary inspection. Isaba receives two of the animals, and Uztárroz, Urzainqui, and Garde take turns receiving the third each year. The first documented ruling in the dispute that gave rise to the tribute dates from 16 October 1375, following the clashes of 1373, although its origin may go back to the invasion by the Cimbri and Baretous peoples in 125 BC. It is considered the oldest treaty still in force in Europe, and the Government of Navarre declared it an intangible Bien de Interés Cultural (Spain's highest level of heritage protection) on 24 January 2011. 13 de julio (desde 1375) Photo: Elgaard (CC BY-SA 4.0) What to see and do in Isaba/Izaba