Valvasone grew up around its castle, and the castle is there for a reason: to control the ford of the Tagliamento. In 1218 the manor was held for the patriarch of Aquileia by Ulvino and Bonfante, founders of the first feudal family, which in 1268 was wiped out during the revolt of Corrado da Valvasone; the patriarch then entrusted the area to Walterpertoldo of Spilimbergo, who in 1273 rebuilt the works along the river, and in 1292 patriarch Raimondo della Torre passed the power to Simone di Cucagna. The most interesting part is how the town was built: before 1300 the nobles decided to ring it with a stone wall, and to manage it they parcelled out the urban land and gave the plots to craftsmen and shopkeepers. The walls, in short, were paid for with building lots. In front of the drawbridge they raised the public loggia, by the Torre delle Ore they dug a well, and in the thirteen fifties they enlarged the built-up area: what came out of it is one of the finest examples of medieval town planning in western Friuli, today among the most beautiful villages of Italy.
In the old parish church of San Lorenzo, which is of the thirteenth and fourteenth centuries, there is a singular fresco: the chained she-devil. Historians consider it important for the history of the plague of 1348, the one that crossed the whole of Europe — the evil chained and painted on the wall, as one does with things that cannot be stopped any other way. At the locality of Pras di Sora, in 1996, a Roman necropolis was discovered. The comune, on the other hand, is brand new: Valvasone Arzene has existed since the first of January 2015, born of the merger of the two comuni, whose built-up areas were already attached to one another. The coat of arms, granted in 2017, puts the two old emblems together, Arzene above and Valvasone below; and the statute settled the most delicate question with a compromise that says everything: the legal seat is at Valvasone, but the town council meets in the former town hall of Arzene.