Karlsburg Castle

The first mention of the Karlburg settlement complex in 741/42 is directly related to the founding of the Diocese of Würzburg. The Carolingian mayor of the palace, Carloman, donated to the diocese founded by Boniface, in addition to 25 royal proprietary churches, a Marian monastery with associated estates and rights in the villa Karloburgo, as reported by three later confirmation charters. In a second donation in the same context, King Pippin the Younger, in 751/53, handed over to the first Bishop of Würzburg, Burchard, the castle and royal court with its associated fiscal district and all revenues to be derived therefrom (castellum ... Karloburg ... cum fisco regali). By the middle of the 8th century at the latest, there was thus a central place with fortifications, a royal court, and a monastery, which was initially in royal hands or those of the Carolingian mayors of the palace and only later transferred to the diocese. The exact founding date of the castle cannot be derived from the sources. It remains unclear whether it was built only in Carolingian times, possibly under Charles Martel, or already in late Merovingian times, perhaps under the protection of the Hedene. Information about the appearance and function of the castle is also lacking. Historical records already characterize Karlburg as an important central place in the early medieval regional history of Main Franconia. Karlsburg, mentioned as a castrum in 1286, met its end in the Peasants' War, when it was burned down between May 15 and June 3, 1525.

Archaeological excavations at the castle took place in 1971/72 and 1974/75 under the direction of Klaus Schwarz. In 1994, a smaller trial excavation was carried out again. Significant insights were also provided by aerial photographs taken in 1992 of the oldest fortifications, which are barely visible above ground.

The evaluation of the excavations by Peter Ettel resulted in a division of the castle's building history into four phases.

Phase A – The Carolingian Complex of the Early Würzburg Diocese Period (Construction around the mid-8th century)

It had an extent of approximately 125 x 120 m with an interior area of about 1.3 ha and was defended by a 5.30 m wide, formerly 1.90 m deep V-shaped ditch, which enclosed the spur in an arc. Behind the inner edge of the ditch, a mortar wall most likely ran, one of the earliest such fortifications in Southern Germany. In the smaller trial trenches inside the castle complex, various post settings and settlement pits were found, testifying to intensive construction and use. Among the finds, a presumably early medieval, decorated bone plate is particularly noteworthy. It probably comes from a small box and is considered evidence of the presence of a socially elevated class of people at the castle.

Phase B – The Ottonian Complex (Construction around 900 – 1st half of the 10th century)

The smaller fortification of the Carolingian castle was abandoned, the ditch filled, and the fortified area expanded to 1.7 ha. This also included previously unused terrain in front of it; the extent was now approximately 170 × 120 m. The new fortification consisted of a again arc-shaped rampart, built up with stones and earth, 9-10 m wide, and a ditch in front of it without a berm. Very likely belonging to this are two further rampart-ditch systems in the forefield, approximately 100 and 200 m away, which correspond in their construction entirely to the main fortification and apparently served as obstacles to approaching cavalry. The type of fortification is typical for complexes from the time of the Hungarian invasions around 900 and in the first half of the 10th century. Numerous post pits and hearths again bear witness to the dense inner settlement. At the foot of the rampart stood a six-post house measuring 6.40 × 5-5.20 m, with a plank floor, a stone boundary to the west, and a brick hearth in the northwest corner.

Phase C – The Salian-Staufer Complex (Construction in the 11th century)

The size of the Ottonian castle was maintained. A mortared wall was erected on the rampart, reinforced by towers placed in front of and partly into the ditch. The three excavated identical towers at relatively regular intervals of 32 to 35 m each had a wall thickness of approximately 1.60 m and a front length of 7.20 m. Two further towers in the southwest can be assumed, as well as a gate at the southwest corner. During the third phase, the rampart on the inside was also widened by 3-4 m to 13-13.50 m, the ditch deepened to 4.50 m and widened to 10-12 m. The fortification thus reached a total width of 25 m.

Among the numerous post holes found here again, a particularly massive construction with very wide and deep post pits, driven into the bedrock, is striking. At the foot of the rampart, a two-aisled post house with a side length of 6 m was again excavated. A large number of ceramic and metal finds prove the intensive and multi-phase use of the interior. Horseshoes, horseshoe nails, and a stirrup indicate the temporary presence of mounted troops.

Phase D – Late Medieval Complex (from around 1200 or mid-13th century to mid-16th century)

The castle complex was now reduced in size and remained restricted to the southeastern spur area. For this purpose, a deep and 30 m wide neck ditch was created, the older fortifications were largely razed, and the terrain in the forefield was leveled. Several remains of the interior buildings are still preserved in their rising walls. Some Romanesque building components probably date back to the Salian-Staufer period. Possibly, Castle D was already built around 1200, parallel to the founding of Karlstadt on the opposite side of the Main, by Bishop Konrad von Querfurt (1198–1202). Of the Gothic buildings, primarily the east wall of the palas building is preserved, which still rises today to a height of 90 m above the Main and offers an impressive view, especially from the Main side. Karlsburg was destroyed during the Peasants' War in 1525.