Bodenseereiter - HBM

From german wikipedia:
The Horseman and Lake Constance is a ballad written by Gustav Schwab in 1826. It is recorded that on January 5, 1573, the Alsatian post bailiff Andreas Egglisperger rode across the frozen Lake Constance to Überlingen. This event with a good ending inspired Schwab to write his ballad with its famous bad ending in 1826.
Plot: A rider in a hurry intends to reach Lake Constance and cross it with a ferry boat. It is deep winter, so he misses the shore and inadvertently crosses the frozen and snow-covered lake, mistaking it for a treeless, undeveloped plain. Once he reaches the other shore, he realizes the danger he has been in. While various people who have arrived congratulate him and invite him back, the rider loses his senses from fright and falls off his horse, dead.
Idiom: A “ride across Lake Constance” refers to a daring act in which the rider only realizes afterwards how risky the undertaking was. In ignorance or misinterpretation of the ballad, this idiom is also occasionally used incorrectly, namely when the danger of failure is seen in advance, i.e. a high risk is consciously taken.

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