Spilimbergo's history begins around the 11th century, when the Spengenberg counts arrived from Carinthia and settled down in the area, acting as the vassals of the bishop of Aquileia.

Following the instructions by count Walterpertoldo II, in 1284 the construction of the Duomo Arcipretale di Santa Maria Maggiore began, which is considered one of the finest romanesque-gothic monuments from the Friuli-Venezia Giulia region.

The War of the League of Cambrai struck the region particularly, turning it into the centre of the conflict between the pro-imperial (Strumieri) and the pro-venetian factions (Zamberlani).

During this period the castle was rebuilt in the style of the Renaissance, and various works of art were created by renowned artists such as Giovanni Antonio Pilacorte, Il Pordenone, Pomponio Amalteo, Gasparo Narvesa, and Irene di Spilimbergo.

In the literary field Gian Domenico Cancianini, Eusebio Stella, and Bernardino Partenio stood out, with the latter being the founder of an academy for the study of the Latin, Greek and Hebrew languages.