Aínsa is a village located in the region of Sobrarbe which began as the capital of the old Kingdom or County of the same name over a millennium ago, in north of the province of Huesca.

In its early days, it was composed of a castle (much smaller than the current one and separate from the village) and a walled enclosure formed by the streets and the churches of San Salvador (since disappeared) and Santa María. Three gates of the settlement's original layout can still be seen today, dating from the eleventh or twelfth centuries. Between the fourteenth and fifteenth centuries, the village expanded to join up with the castle. The Plaza was built along with several houses in the lower part of the village, giving rise to a second walled enclosure. This is preserved for the most part masked by the houses that were built against its interior face. Various stretches of the walls without buildings are nevertheless visible in different parts of the village. Five of the seven gates of these two walled areas can be admired today: Portal de Abajo, Portal de Afuera, Portal Alto, Portal de Tierra Glera and Portal del Callizo.

The village is strategically located on a hilltop at the confluence of the Cinca and Ara rivers, at an altitude of 589 metres, thus dominating its entire surroundings. In a privileged setting between the National Parks of Ordesa and Monte Perdido, Sierra y Cañones de Guara and Posets-Maladeta, Ainsa lies at the crossroads of the most important travel and transportation routes in this area of the Pyrenees.

In a mound to the north of the village, the remains of some small constructions have been found although not yet subjected to further study, along with some samples of Roman ceramics. In any case, in the absence of documentary evidence, we know nothing of the historical evolution of Aínsa until 1124, when Alfonso I granted it a Municipal Charter with privileges equal to those of the city of Jaca.

The legend of the Cross of Sobrarbe takes us some way further back to 724, telling of Christians who had fled from Muslim rule gathering in Aínsa to undertake the reconquest. According to this legend, the Christian troops led by Garci-Ximeno managed to win the battle thanks to the appearance of a shining cross on an oak tree, which gave them the courage to recover the city. This victory is still commemorated today, with the biannual “La Morisma” festivities. Indeed, the symbol of the Sobrarbe is a cross on a tree, an image which also appears in one of the quarters of Aragon's coat of arms.

From the thirteenth to fifteenth centuries, it was granted a large number of privileges by the different monarchs who reigned during this time, testament to how important the village of Ainsa was in the Middle Ages. This was especially in terms of trade, as Ainsa hosted various large annual fairs, making it the main nucleus of a region that was more populous than it is today.

The seventeenth and eighteenth centuries saw the deterioration of this prominence, with the exception of the Collegiate Church that acquired more power than in previous centuries. This decline was aggravated by the War of Succession and the Carlist wars.

Aínsa continued in this way until the 1940s when it regained its commercial weight in the region. This influence was no longer anchored in the historic centre, but arose as a result of the crossroads at the foot of the hill. All this has allowed both the authenticity of the buildings and the structure of the medieval village to be preserved intact.

In 1965, the Old Town of Aínsa was declared a Historic-Artistic Site, with the church and the castle having been classified as National Monuments since 1931. Subsequent restoration work has returned the old village to its former beauty.

About half a century ago, its municipal area was much diminished, but the alarming depopulation of the region prompted the State to initiate a policy of merging municipalities in order to concentrate efforts. The current municipality is thus called AINSA-SOBRARBE and covers an area of 285 km2, making it one of the largest in Upper Aragon and incorporating twenty-three small villages and hamlets within its boundaries. The trade and tourism sectors have seen the strongest development, although agricultural and livestock farming still takes place in the area.

Additional inhabited centres:

http://www.villadeainsa.com/portada-seccion/nucleos-ainsa-sobrarbe 

The population centres that make up the Municipality of Aínsa-Sobrarbe are:  Arcusa, Arro, Banastón, Bruello, Las Bellostas, Camporrotuno, Castejón de Sobrarbe, Castellazo, Coscojuela de Sobrarbe, El Coscollar, Gerbe, Griébal, Guaso, Jabierre de Olsón, Latorre, Latorrecilla, Mondot, Morillo de Tou, Olsón, La Pardina, La Ripa, Paúles de Sarsa, Santa María de Buil, Sarratillo, Sarsa de Surta and Urriales.