About 1200 the patriarchs enfeoffed the Venzone estates to the Mels noble family residing at Mels Castle near Udine (progenitors of the House of Colloredo-Mansfeld). The local lords had the town surrounded by a massive double line of walls with several watchtowers and a moat, starting in 1258. After they had ceded the "comune" to the Counts of Gorizia, Venzone was re-acquired by Patriarch Bertram of St. Genesius in 1336. The buildings suffered severe damages during the 1348 Friuli earthquake. From 1351 the fief was held by the Habsburg duke Albert II of Austria, before Venzone, together with most parts of Friuli, was conquered by the Republic of Venice and incorporated into the Domini di Terraferma after 1420.