In the picturesque village of Siddi, the Church of San Michele Arcangelo stands as an authentic architectural jewel dating back to the second half of the 13th century. This sacred building, hidden in the urban periphery, represents a treasure of inestimable historical and artistic value. Its structure is distinguished by an unusual plan with two naves of different sizes, culminating in a single apse. The façade, divided into two distinct mirrors, has an entrance portal for each nave, enriched by a central oculus and accommodation for ceramic basins, typical elements of Sardinian Romanesque architecture. Of particular interest is the portal of the minor nave, which houses a relief of extraordinary iconographic importance. This is divided into four panels, each populated by anthropomorphic figures that scholars interpret as a representation of the cycle of the 'fall'. In this visual narrative, Lucifer, Adam, Eve, the Archangel Gabriel and the Creator can be identified, offering the faithful and scholars a fascinating theological and artistic interpretation.