"The Haidbauer incident, known in Austria as der Vorfall Haidbauer, took place in April 1926 when Josef Haidbauer, an 11-year-old schoolboy in Otterthal, Austria, reportedly collapsed unconscious after being hit on the head during class by the Austrian philosopher Ludwig Wittgenstein."

https://en.m.wikipedia.org/wiki/Haidbauer_incident