The Church of St Peter Apostle stands on the rural site known as 'de Milis Piccinnu'. This area has an ancient history, having been inhabited as early as the Nuragic Age and frequented during the Roman-Republican period. As a villa, the medieval settlement already existed in 1388, as its representatives signed the peace between Arborea and Aragon. It gathered around its parish church, the oldest attestation of which dates back to the beginning of the 12th century and is found in the first act of the Condaghe di Santa Maria di Bonarcado, by which the Arborean judge Constantine I de Lacon-Serra founded the Camaldonian monastery of Bonarcado, affiliating to it, among others, the domo de sanctu Petru de Milii Piccinnu, endowed with goods in land, men and livestock. The early-medieval church, of whose masonry unfortunately no traces remain, was rebuilt in limestone ashlars on a single-nave plan to be ascribed to the mid-13th century; the apse was demolished and the postern part extended in modern times. The façade and sections of the flanks are preserved, fixing the length of the Romanesque building at just over 9 metres. A ribbed bell tower with an ogival light rises from the façade; a wall mullioned window is still visible on the façade, which has now been plugged up, and an architraved and lunetted portal opens, allowing access to the hall, whose jambs, made of basalt, appear to be reused ashlars, probably from the nearby nuraghe. Details, such as the elaborate outline of the outlet arch and the small arches of the mullioned window, indicate similarities with the extension structures of the church of Santa Maria di Bonarcado, dating from 1242-1268.