Runkelstein Castle (German: Schloss Runkelstein; Italian: Castel Roncolo) is a medieval fortification on a rocky spur in the territory of Ritten, near the city of Bolzano in South Tyrol, Italy. In 1237 Alderich Prince-Bishop of Trent gave the brothers Friedrich and Beral Lords of Wangen permission to construct a castle on the rock then called Runchenstayn.
In 1274 it was damaged during a siege by Meinhard II of Tirol, who after winning the war against Heinrich Prince-Bishop of Trent, entrusted the castle to Gottschalk Knoger of Bozen. In 1385 the Niklaus and Franz Vintler wealthy merchant brothers from Bozen bought the castle. Niklaus was counselor and financier of the Count of Tyrol, Leopold III, Duke of Austria, which allowed them to buy the castle a type of residence unfitting in this time for people of their rank. The brothers Vintler commissioned a vast restructuring of the castle: a new defence wall, moat, a cistern and more rooms were built. In 1390 the construction of the Summer House began. The house was painted with frescos, for which the castle is most famous today, inside and outside. The frescos topics were of literary nature, depicting i.e. King Arthur and his knights, Tristan and Isolde. The family also commissioned the frescoes in the Western and Eastern Palace. They were created by an unknown masters and some of them depict scenes from Pleiers romance Garel.
In 1407 the monetary conflict between Frederick IV, Duke of Austria “mit der leeren Tasche“ (with empty pocket), Count of Tyrol and wealthy Tyrolean noble families resulted in open war. The Vintlers were drawn into these disputes and Runkelstein was besieged. Niklaus, who had allied with himself with the nobles in the "Hawk League" lost all his wealth and possessions. His brother Franz, who had allied with the Duke remained owner of the Castle until Sigismund, Archduke of Austria “der Münzreiche” (rich with coins) acquired it.