The castle has always guarded over the entrance to the Val Casies-Gsieser Tal valley. It was first documented in 1126 and was the main administration castle of Welsperg for about 800 years until 1907. It is open for visitors in summer.

Castel Monguelfo is not only a particular castle complex, but is also the oldes castle of Alta Pusteria. Castel Monguelfo, also called Castel Welsperg, is undoubtedly a particular castle complex and it is a core castle. One of the oldest parts of the castle is the high donjon, which has been constructed in 1126. The brothers Schwikher and Otto von Welsperg had this castle built. In these days the Lords of Welsperg were one of the most significant noble families of Tyrol. Due to their smart commercial activity and administrative work as well as their wedding politics they build up a fortune and increased their importance. For this reason in 1359 Georg von Welsperg purchased the castle on the opposite, Castel Tesido. Consequently both castles were in possession of the Lords of Welsperg. In the 15th and 16th century Castel Welsperg was considerably enlarged and also reconstructed. In 1765 there was a fire which destroyed parts of the castle complex, including the great hall and the commercial building. Despite of the fact that there were renovation works, the castle started decaying and has no longer been inhabited.

Today the castle complex is venue for numerous concerts and exhibitions, organised by the board of trustees.

The ruin and the Castle can be reached on foot via the hiking trail "Kleine Schlossrunde" and "Große Schlossrunde".
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Coming from Innsbruck/Brennero (A): Drive on the Highway of Brennero (A22) until the exit Bressanone/Val Pusteria, then go on along the SS49-E66 for about 58kms until you arrive in Monguelfo. To get to Tesido and the Val Casies Valley, we recommend to take the exit West in Monguelfo. Coming from Lienz (A): You can reach us also padding by Lienz in Westtyrol (A). You have to cross the Austrian-Italian border between Ahrnbach and Winnebach (B100-E66) and drive on the SS46-E66 until Monguelfo. To get to Tesido and the Val Casies, we recommend to take the exit West in Monguelfo.