Basilica of St. Simplicius, Olbia, Italy

Archaeological Studies and Construction Phases         

Recent archaeological investigations have significantly deepened our understanding of the construction history of the Basilica of San Simplicio, revealing five distinct building phases—surpassing the previously recognized three. These discoveries shed light on the architectural evolution of one of northern Sardinia’s most important religious landmarks. The original church was a modest three-nave structure, characterized by a shorter length—spanning only four pairs of arches—a lower roofline, and a simple wooden covering. This early phase also included essential foundational elements: four interior columns and four supporting pillars for the arches. The second phase of construction marked a significant shift with the introduction of barrel vaults over the side aisles, replacing the original wooden roof. These vaults improved both the durability and acoustics of the interior.

In the third phase, the builders raised the church’s roof to enhance vertical space and increase illumination through the clerestory windows. The fourth phase extended the structure by adding two additional pairs of arches, effectively lengthening the nave and relocating the façade further west to the final pair of pillars. The fifth and final phase, believed to have occurred in the 13th century, introduced the bell tower and a further extension of the building. The façade was once again moved forward, this time to its current position, absorbing the newly constructed elements and creating the basilica’s present form. A three-light window was later added by breaking through the upper façade wall, likely to enhance natural lighting in the nave.

Architectural Style and Materials 

The Basilica, as it stands today, reflects a stylistic finish representative of Lombard Romanesque architecture, the hallmark of the final groups of craftsmen who worked on it. The entire structure is primarily built from local granite, a material that gives the building its austere and timeless appearance, with some brickwork additions introduced in later modifications.

Earlier Structures and Religious Significance     

The basilica is situated on a small hill that was used as a burial ground from the Roman Republican era through to the Middle Ages, highlighting the site’s long-standing sacred significance. While not definitively proven, there are conjectures—though largely based on 17th-century sources—suggesting the presence of a Palaeo-Christian church on this site, possibly dating to between 594 and 611 AD. This earlier structure, if it did exist, would have been erected near or upon the remains of a Roman temple, making the site a continuous place of worship across pagan, early Christian, and medieval periods.

Uncertain Origins and Patronage

The exact date of the foundation of the earliest church remains unknown, and to date, there is no definitive record identifying its original patrons or sponsors. However, recent studies of masonry techniques and construction measurements suggest that the first phase of construction likely predates the 11th century. This includes the building of the apse, sections of the perimeter walls, and initial structural columns and pillars. The later expansion phases—especially the lengthening of the nave and addition of new architectural elements—are possibly connected to the Church Reform movement of the late 11th century and may have been carried out under the influence of papal legates sent by Pope Alexander II or Pope Gregory VII.

Ecclesiastical Complex and Urban Context

Though still speculative, some scholars hypothesize that next to the original basilica—the only surviving medieval structure in the ancient town of Civita—there may have stood the judicial chancellery, a bishop’s residence, or other clerical spaces. Based on architectural characteristics and archaeological evidence, it is plausible that the basilica was once part of a Byzantine-style episcopal complex, or Insula episcopalis, suggesting that the area served not only as a place of worship but also as a center of ecclesiastical administration.