The Hidden Gem of Germany || Lake Constance

1:60 Meersburg became after Reformation the seat of the Prince-Bishop of Constance (the citizens of Constance had thrown him out). For the first centuries he used the old castle (the grey one at the left), which according to legend was founded by Frankish king Dagobert (of the Merovingian dynasty) in the 7th century (but the current castle was built around 400 years later). During the Baroque era in the 18th century the bishops built the New Palace and a Seminary; the yellow palace between did hold the stables and coach house; it is now used by the State Vineyard.
2:15 He is right. It was built and used until 1803 as nunnery and came into possession of the state of Württemberg in 1806 by Napoleon, who also appointed the Duke of Württemberg as King of Württemberg. Since then it became the summer residence of House Württemberg.
4:40 Mainau Island was 1271 – 1806 an estate of Deutscher Orden (Teutonic Order); the palace was built by a famous architect of this Order, Johann Caspar Bagnato, in the 18th century. After 1806 it came to the Grand Duchy of Baden, which sold it to an Hungarian prince of House Esterházy; his illegitimate son sold it back to Baden; in 1928 it was inherited by Victoria of Baden, since 1881 married to King Gustav V of Sweden. In 1932 it was given to Count Lennart Bernadotte who had resigned from the Swedish royal house and line of succession to marry a commoner. He created then the park and opened it to the public; it is now managed by the children from his second marriage.
6:50 Bregenz was founded by the Celtic tribe of the Brigantii, who were defeated in 15 BC by Romans (including a naval battle on the lake). To the Romans the lake was Lacus Brigantiae; to Germans it is the Bodensee after the former Imperial Palace at Bodan.
17:35 The bishop's palace mentioned before.

For your next trip to Lake Constance I would recommend to visit Überlingen and also Konstanz / Constance.