Castel San Pietro: A Medieval Thun Castle Ruin in Italy
Site at a Glance
- Rating
- 4.3
- Popularity
- Very Low
- Country
- Italy
- Primary era
- Medieval
- Eras represented
- Medieval, Early Modern
- Civilizations
- Holy Roman Empire
- Site type
- Military
- Remains
- Castle
On this page8 sections
History
Castel San Pietro is a medieval hilltop castle ruin in Italy, above Ton in Trentino’s Non Valley, whose oldest surviving elements date from the last quarter of the thirteenth century. Associated with the Thun family, a noble house of the Trentino-Tyrol region, it formed one of four castles securing the Thun lordship around Ton. Its position on a rocky spur helped control the road below, which carried both military and economic importance.
Origins and the Thun lordship
The castle stands on the left side of the Noce valley, in Valle San Pietro, about 2 kilometres from Vigo di Ton. Its western approach was protected by a steep drop toward the Torrente Rinassico. A road beside the stream was traditionally identified as a Roman route linking the left side of the Non Valley with the Via Claudia Augusta, the imperial road that connected the Po Valley with the northern Alpine region.
Castel San Pietro first appears in written records in 1321. During the Nonsberg aristocratic feud, a conflict among noble families in the Non Valley, the Lords of Arz besieged the Thun-held castle in 1337. The Thun were first formally enfeoffed with it in 1338, meaning that the bishops of Trent granted the property or its rights to them as feudal lords. The castle later appears as a Thun fief in fifteenth-century grants issued by the Tridentine bishops Georg of Liechtenstein, Alexander of Masovia, and Johannes of Hinderbach.
In 1375 and 1400, Guarimbert III of the Thun family received the fortress as a fief. It then passed to his son Erasmo. The castle’s origins were later connected with the Roman period because of its unusual cylindrical tower, the lack of earlier written references, and a proposed alignment with an ancient route over the Roccapiana pass. That interpretation is not supported by the historical evidence identified by Walter Landi. Instead, construction has been attributed uncertainly to Guarimbert II of Thun, who died in 1300, or to one of his brothers, Simon I or Konrad.
Defence, chapel, and changing use
From the second half of the fifteenth century, the Thun entrusted the castle to a castellan, an officer responsible for administering and defending a castle for its lord. In 1525, during the Peasants’ War, a series of rural uprisings in the German-speaking lands, Siegmund of Thun reinforced the garrison and strengthened the walls after rebels had attacked several other castles.
The castle chapel, dedicated to Saint Peter, was consecrated on 23 April 1504 by Francesco De La Chiesa, titular bishop of Drivastum and suffragan to the Tridentine prince-bishop Ulrich IV of Liechtenstein. A titular bishop held a bishop’s title without governing the corresponding diocese, while a suffragan bishop served under a higher-ranking bishop within an ecclesiastical province. The Thun requested that the chapel, like the chapel of Saint George at Castel Thun, be opened for worship on Sundays, major feasts, and the feast days of Saint Lawrence on 10 August and Saint Martin on 11 November.
From the sixteenth century, Castel San Pietro served mainly as a hunting residence and weapons store. In 1635, Giacomo Annibale Thun left 300 ragnesi, a historical regional currency, to fund twelve Masses each year at several Thun chapels, including Saint Peter’s. Francesco Zamboni added 100 ragnesi for four further Masses.
Abandonment and later ownership
By the late seventeenth century, the castle was largely abandoned, although religious services continued in the chapel. The deterioration may have been hastened by the so-called roof tax, which probably encouraged fires in the roofs of little-used noble buildings. In 1695 the chapel’s altar was described as unconsecrated and its roof as being in very poor condition. In 1710 the chapel was still mentioned within the castle, while the complex was again described as abandoned. Six Masses a year continued during the eighteenth century, and the chapel last appears in visitation records in 1766.
The 1774 Atlas Tyrolensis, an eighteenth-century map of the County of Tyrol, marked Castel San Pietro as a ruined castle. Johanna von Isser Großrubatscher’s drawing of 1846 also showed the site as a ruin, although it remained listed as a Thun fief in 1851. In 1926 the ruin was sold to the Bohemian branch of the Thun family and later resold to the Counts Martini of Mezzocorona, who are stated to remain its owners.
Remains
Layout and defensive enclosure
The ruin occupies the narrow summit of a rocky height at 864 metres above sea level. Its surviving plan forms an ellipse oriented from northwest to southeast, approximately 40 to 45 metres long and 15 to 17 metres wide. The castle’s remains are arranged within fragments of an inner and an outer defensive enclosure. The inner wall was about 50 centimetres thick and approximately 90 metres long, enclosing around 475 square metres. The outer wall was about 80 centimetres thick and enclosed roughly 300 square metres. Both survive only in fragmentary form.
Cylindrical keep and shell tower
The central feature is a cylindrical keep that tapers slightly toward the top. Built from locally quarried limestone, it has a base diameter of 5.8 metres, stands 11.5 metres high, and has walls up to 1.45 metres thick. Its visible entrance is 4.6 metres above ground level. A graphic reconstruction by Franco Lancetti proposes an internal diameter of about 6 metres, walls around 1.4 metres thick, and an original height of approximately 15 metres. The keep and the inner defensive wall belong among the oldest elements of the castle and were built in the last quarter of the thirteenth century. Fragmentary traces indicate that another building may have been attached to the inner wall during this early phase.
In the northwestern part of the enclosure stood a shell tower, a tower formed by a curved outer wall that was less substantial on its inner side than a fully solid cylinder. Its entrance gate was about 1 metre wide. Sparse remains survive, and one or more arrow slits can still be recognized in fragments of the defensive walls. The outer wall and shell tower date from the fourteenth century and use a building technique somewhat different from that of the older keep and inner enclosure.
Later buildings and chapel foundations
Ruins of additional buildings occupy the eastern side of the enclosure. Their poor condition leaves their original functions uncertain, although their development may be connected with the castle’s later use as a hunting residence and weapons store.
The chapel dedicated to Saint Peter probably stood in the eastern part of the castle. Its surviving remains include the foundations of an apse, the curved end of a chapel, approximately 3 metres in diameter. The site is preserved as a ruin, with the cylindrical keep, defensive-wall fragments, shell-tower remains, later building traces, and chapel foundations forming its principal physical evidence.
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