At first sight, it looks like a normal single-nave church, without friezes or external decorations, built in the courtyard of the Serravalle Castle in Bosa, a picturesque medieval village in the Planargia region. In reality, the church of Nostra Signora de sos Regnos Altos hid its priceless wealth in the internal walls, under the plaster. ...and it may still be jealously guarding some secrets. One is linked to its founding, with no source, so the theories formulated vary between the 12^th and 14^th centuries. Subsequent renovations, also undocumented, fuel the mystery. The church probably served as a palace chapel inside the castle. It has a rectangular hall with a semicircular apse and two entrances, one on the façade and one on the north-east side. At the end of the 19^th century, a decision was made to extend the hall to the east and this involved the destruction of the original apse. The great revelation, however, came to light during the consolidation works in the two-year period of 1972-73: while removing the plaster, a surprising series of frescoes appeared, which had originally occupied the entire perimeter of the building and are interrupted on the eastern side due to demolition of the ancient apse. The work dates back to the 14^th century and is attributed to Tuscan craftsmen sent by John of Arborea, brother of Marianus IV. The painting is displayed on two registers, separated by a decorative frame and inspired by the themes of the preaching of Saint Francis: between the Adoration of the Wise Men, the Last Supper and Saint George slaying the dragon, you will also see the only Sardinian portrayal of the legend ‘of the three living and the three dead’. The virtues celebrated are poverty, chastity and humility, topics dear to Franciscan spirituality.

The church was originally dedicated to Saint Andrew. According to a folk legend, in 1847 a child found a wooden statuette depicting a Madonna among some of the ruins of the castle. The artefact was given the name of Nostra Signora de sos Regnos Altos (Our Lady of ‘sos regnos altos’) and placed in a niche inside the church, where it is still found today. The news of the discovery of the statue of the Madonna, in honour of whom the name was changed, spread rapidly and became a destination for pilgrimages and a reason for prayer and veneration. The number of devotees continued to increase, hence the origin of the celebration that has been taking place every year since the mid-19^th century. In mid-September, the narrow streets of the medieval district of sa Costa are filled with decorations, lights and colours. Open spaces and alleyways host sos altarittos, which are small altars decorated with flowers, typical filet lace and statuettes of the Madonna. You will hear the sound of the gosos, heart-rending liturgical songs, and you can enjoy the festive tables with excellent Malvasia wine and typical cakes.

In addition to the medieval castle, a place of legendary tales and a captivating panoramic viewpoint over the valley, in Bosa you can visit the ancient tanneries on the left bank of the Temo river or stroll among the picturesque multicoloured houses on the opposite bank and visit the oldest Romanesque church in Sardinia, San Pietro extra muros.