The crest from the Tertiary period, which stretches eastward from Günzburg on the southern Danube bank, challenged to a settlement particularly protected by nature already in pre-historical time. At the village Reisensburg the crest sloping down steeply to the north and south is cut by two artificial deep transverse ditches, thus forming a mountain hill completely surrounded by a steep slope. Continuous settlements from the later Stone Age till the Roman Empire, especially from the Urn Field Period, are proven by findings. From the garden of today's castle and from its northern steep slope numerous living pits and other settlement tracks were uncovered. Large tone vases, bowls, plates and other tone table-ware remains, in addition to spindle weights, bone needles, awls, querns, fire supports, as well as sporadic bronze items are the witnesses of a long-continuing settlement of the castle mountain, which falls approximately into the time around the first millenium before Christ.
In the later Celtic times the mountain probably served as a refugee castle. In the epoch of the Roman fort Gontia (the today's Günzburg) a Burgus (Roman watch-tower) probably stood there. After the land was occupied by the Alemanns the Reisensburg was first mentioned as Civitas Rizinis by the Geographer of Ravenna (around 700 AD). There he relies on a geographical description of the Gothic Athanarid, who lived around 550 AD. The identification of this Civitas Rizinis with our Reisensburg is also very likely from languistic history, particularly as some different linguistic transition forms, as Risinis Burk etc. were used in the Middle Ages. Thus the Reisensburg is among the oldest Alemannic castles. It was probably extended under Theoderich the Great, under whose protection the Alemanns placed themselves after their defeat by the Franconia king Chlodwig in 496 AD, as Prof. Dr. Beyerle tried to prove in a very remarkable study.
In the tenth century the Reisensburg was in the possession of the Bavarian dukes. Probably Kunigunde, the sister of the Swabian dukes Bertold and Erchanger who were executed in 917 by king Konrad the First, brought in the Reisensburg as wedding property when marrying the Bavarian duke Luitpold. By the way, in second marriage Kunigunde became German queen by marrying king Konrad, who let her two brothers execute. Some decades later the Bavarian duke Bertold, son of the Bavarian duke Arnulf, in the year 955 betrayed the approaching army of Otto the First of Hungary before the famous battle on the river Lech plains, as reported by the Vita sancti Oudalrici (the life of the holy Ulrich, bishop of Augsburg). This Bertold or Berchtold was deposed as duke of Bavaria by Otto the First and exiled to the Reisensburg out of revenge.
Afterwards the Reisensburg was assigned as feoff to the House of Eberstal, some of whose members later called themselves after the Reisensburg. The Lords of Risenburc seem to have possessed the castle to the end of the 13th century, until the Counts of Berg appeared as Margraves of Burgau in 1295, to whose possession also the Reisensburg belonged. The last male Margrave of Berg married a daughter of the Margrave of Hohenheim, whose sister was the wife of Rudolf the First of Habsburg. For lack of male descendants the margravate Burgau including the Reisensburg then fell to Habsburg. The house of Habsburg, which ran into debt due to the many wars, pawned the Reisensburg to different members of the nobility, so to the Lords of Knoringen and later to the Knights of Stain, which had their grave yards in the nearby parish church of Jettingen. Their gravestones from the late Gothic and early Renaissance are still preserved and are very remarkable from the point of view of art history. Later the Reisensburg came to the Noble Giel of Gielsberg, to the Lords of Eyb, and then to the Barons of Riedheim. In 1920 the Günzburg attorney Vogel acquired the Reisensburg. His widow has preserved it to the best of her ability till 5th March 1966. On this day the castle became property of the "International Institute for Scientific Cooperation".
The today's castle system probably originates mainly from the 17th century, after the earlier Gothic castle burned down to the massive keep in the Thirty Years' War. The later castle of the 17th century encases this old giant, that became a landmark of the whole area with its 35 meters height and a wall thickness of 3,5 meters. This Romanesque keep is built from massive rough stone, with pretty pinnacles and corner towers of the late Gothic period on top. From the platform of the tower the view roams over the Jura hills to the north, and eastward down the Danube as far as to the cities of Lauingen and Dillingen. On clear days Ulm Cathedral can be seen in the west. In the south the view roams over the village Reisensburg nestling against the contour of the castle mountain, and further away over the Swabian-Bavarian High Plain where on clear foehn days the Alps light up as southern boundary line.
The castle chapel situated below the castle with its many nice gravestones of the old castle lineages originally belonged to the castle but is now parish church of the village. From the point of view of art history the most valuable piece is considered to be the magnificent relief of Loy Hering with the Annunciation (1523).
(translated from "Chronik der Reisensburg")