[1] This theory is based on a source from 1548,[2] and was supported by Joseph von Laßberg who lived in the castle during the 19th century.
A charter issued by Frederick Barbarossa on 27 November 1155, citing older, questionable sources, mentions that the boundaries of the Bishopric of Constance were established by Dagobert himself[3] indicating that Dagobert was personally involved in establishing rulers in the region.
The second theory is that the castle was built in the early 12th century, and based on the name of the tower an association with the earlier Merovingian king was created.
Joseph von Laßberg also presents the theory that the tower was built on the site of an earlier destroyed castle.
He states that the castle was destroyed by Duke Gotfrid of Alemannia who was at war with Dagobert's successor and rebuilt 80 years later by Charles Martel.
It appears that the castle was owned by the Hohenstaufens for a while, because in 1213 King Frederick II celebrated the Holy Week in Meersburg.
He departed from Meersburg[6] to head south into Italy to fight Charles I of Anjou and attempt to reclaim the titles stripped by the Pope from his father.
A few years later, in 1268 the castle came totally under the ownership of the Bishopric of Constance[7] However, even as a residence for a bishop, the Meersburg was the site of several battles over the following centuries.
Baron Nikolaus I of Kenzingen was elected bishop by supporters of the Pope while Albrecht of Hohenberg was chosen by the Holy Roman Emperor.
Nikolaus quickly traveled to Avignon, in France the seat of Pope John XXII to have his appointment confirmed.
When Duke Otto of Austria requested his help against the Bohemians, Louis left Meersburg and confirmed Nikolaus as bishop.
In 1352 Johann III Windlock from Constance was installed at the castle, he proved to be an autocratic ruler and was disliked by the people and local nobles.
Following a dispute with Konrad of Homberg-Markdorf and the Abbot Eberhard of Reichenau, he was killed by soldiers while in his palace in Constance.
In 1841 Jenny's sister Annette von Droste-Hülshoff, the famous German poet, moved to the castle where she would spend the last eight years of her life.