Spilimbergo gets its name from the Carinthian Counts Spengenberg, who settled here around the 11th century.

The first docu­­­­­­­­­ment that mentions the castrum de Spengenberg dates back to 1120; however, the site’s history goes back to Roman antiquity, as it was located near the Roman road that crossed the Tagliamento river connecting Sacile to Gemona and Germany. Moreover, the presence of the fortified settlement of Gradisca sul Cosa bears further witness to a millenarian settlement.