Castle of Trebiano, Medieval castle in Arcola, Italy

Castle of Trebiano is a fortified structure built on elevated terrain near Arcola with stone walls and multiple towers. It commands views over the surrounding hills and valleys from its position above the landscape.

The castle is documented in 963 in a diploma of Emperor Otto I of Saxony, placing its origin in the 10th century or slightly earlier. It belonged to the Diocese of Luni as a bishop's residence, and the diocese kept it after the village passed to the Lords of Trebiano in 1039. In the 13th century it came under the Republic of Genoa, and in 1442 Antonio Biassa, of a Spezia noble family, conquered it.

The castle stands on the hill directly above the medieval village of Trebiano, in the municipality of Arcola, and is reached on foot along the village lanes climbing to the summit. The site has no windows, only long narrow slits in walls up to 20 metres high, so the walk is exposed to sun and wind. Sturdy shoes help on the steep, uneven approach.

The castle has no windows, only long narrow slits in walls up to 20 metres high, and four large towers set into the curtain wall. Its plan is square, or rather sub-pentagonal, following the hilltop above the village.