The Spanish language did not spring up all at once, and if you want to see a place where it first stepped on to the page, you come to San Millán de la Cogolla. In two monasteries, Suso above and Yuso below, in a green valley of the Sierra de la Demanda, monks of the tenth and eleventh centuries made notes in the margins of a Latin manuscript, translating hard words into the speech of ordinary people, in a form that has been identified as one of the earliest written Castilian and, in a few lines, Basque. Those notes are known as the Glosas Emilianenses, and the monasteries were listed by UNESCO in 1997.
Suso, the old monastery, is a small stone complex built into the rock of the hillside, with horseshoe arches that show Visigothic and Mozarabic influence, and caves where the hermit Emilian is said to have lived in the sixth century. Yuso, the newer monastery, lies in the valley below, a large Renaissance and baroque building with a fine church, a library and a famous collection of ivory reliquaries. The poet Gonzalo de Berceo, who wrote in the vernacular in the thirteenth century, was educated here and is regarded as the first named poet in Castilian.
For riders, the valley of the Najerilla is a pleasant, calm place. The approach from Nájera, on the Camino de Santiago, is a quiet road through vineyards and poplars, and beyond San Millán the mountain road climbs through oak and beech toward the Sierra de la Demanda, with views of snowy peaks in winter. Bends are gentle, traffic is light and the surface is good. Spring is green and cool, and in autumn the vines turn red.
San Millán de la Cogolla is a village of about three hundred people, so fuel is in Santo Domingo de la Calzada, fifteen kilometres away, a town of about six thousand with a cathedral famous for a live rooster and hen kept in a Gothic coop in memory of a pilgrim miracle. Visits to the monasteries are by timed tour, so check the schedule before you arrive. The best meal in the valley is the local lamb or a dish of potatoes with chorizo, and a glass of Rioja.