The Church of Saint Nicholas of the Hospital was built between 1280 and 1289, a date suggested by the Romanesque features of its main façade. The only original element that has survived intact is the small bell gable, while the area around the portal has been significantly altered over the centuries.

In addition to its function as a place of worship, the church also housed a cloistered monastery for Benedictine nuns.

Today, the sacred building presents a rectangular layout with a single nave that sits slightly below the level of the courtyard. It was once fully decorated with frescoes, as evidenced by a surviving fragment to the left of the entrance: the Virgo Lactans, a 14th-century painting of the Virgin Mary breastfeeding the Christ Child. This fresco stands out for its remarkable warmth and expressiveness, capturing a transitional moment between the hieratic rigidity of Byzantine tradition and the emerging search for volume and realism in medieval art. The Virgin’s head is gently tilted, her brow arch prominently marked—a common feature in medieval painting. Yet the tender gaze directed at her Child and the fluid drapery reveals a clear intent to convey dimensionality and emotional depth. The Christ Child, depicted in profile, appears to move naturally, hinting at later artistic trends toward dynamic representation of the human form.

Below the fresco is a niche, its inner walls still bearing traces of additional painted decorations, now partially obscured by later structural changes.

Continuing along the nave toward the presbytery, one encounters a small iron grille. Some scholars believe this feature dates back to when the building housed a cloistered convent, allowing the nuns to observe the liturgy without being seen. Others suggest it may be a reused architectural element—possibly part of a medieval mortuary drain from a period when the complex was under the care of the Knights Hospitaller.

On the right-hand side, near the center of the nave, several burial niches have been uncovered—hidden for centuries, likely sealed off during the 18th-century renovations.