And whole armies crumbling as word spreads that the top guy is dead… well, that happened a lot.
I read this idea a fair bit in wargames rules – but did it really happen? A lot? At all?
Harold, Richard III and James IV of Scotland all died in battle but their deaths were not the cause of the battlefield defeat but as a result of defeat (possible argument over the timing of Harold’s death I suppose – but no evidence it precipitated a rout).
Gustavus Adolphus was killed in battle but his army didn’t collapse.
I’m sure there have been instances, but lots?