The Pomerio castle is divided into several buildings that have developed over the centuries around a central rectangular courtyard.

The intervention that started the construction was promoted by Bishop Beltramino Parravicini, who in the fourteenth century rebuilt the castle where an older building dated to the eleventh-twelfth century stood, seat of a military garrison: this explains why the castle was built in flat area.

The presence of the pre-existing building is confirmed both by the tower in large blocks of gray Moltrasio limestone, still clearly visible from the Erba-Como provincial road, and by the discovery of a very thick wall with a visible foundation up to 5 meters deep, which it was investigated in 1982, as reported by Fernanda Isacchi, during excavation works close to the rear facade of the complex.

The castle is dated to the twelfth – fourteenth century on the basis of the observations made on the occasion of the Census of the Castles of Lombardy, published in 1991 by the Lombardy Region.

In the second half of the last century (1973-1982), on the occasion of the restorations carried out in anticipation of the transformation of the castle into a hotel and restaurant, unpublished fourteenth-century frescoes were discovered inside the oldest portion of the castle. In particular, frescoes representing the coats of arms of the Parravicini and Carpani families have been identified on the first floor, while on the second floor, in the banquet hall, two late Gothic frescoes have been restored: one represents a Madonna enthroned with the Child, the other a figure of a saint recognized as Saint Benedict.

With regard to the centuries following the Middle Ages, on the basis of documentary and archival sources, collected and analyzed by Virginio Longoni, we know that in 1480 two members of the Parravicini family lived in the castle, priest Bernardo and friar Giovanni, both belonging to a brotherhood of the third. Franciscan order; in 1647 the Archinti family became the owner of the complex and, in the same century, the property passed back to the Parravicini family, who in 1714 sold it to the Corti family.

At the beginning of the nineteenth century it was the Courts who set up a silk business inside the castle; a century later, at the beginning of the twentieth century, the complex underwent a total renovation in neo-Gothic style: on this occasion some pointed arched windows were opened on the western facade.

On the occasion of the interventions carried out in the second half of the last century, in addition to the interventions on the oldest walls, which allowed the discovery of the frescoes of the fourteenth century, it should be noted the discovery, in the internal courtyard of the castle, of two “throwing wells”.

The excavation has led to the recovery of ceramic fragments dated between the fourteenth and sixteenth centuries: these broken crockery, and for this reason thrown, offered valuable information on daily life at the castle between the late Middle Ages and the Renaissance. The finds are kept at the Civic Archaeological Museum of Erba.