According to this popular, but unsubstantiated, legend, Hatto II was a cruel ruler who oppressed and exploited the peasants in his domain.
[1] He used the tower as a platform for archers and crossbowmen and demanded tribute from passing ships, shooting on their crews if they did not comply.
During a famine in 974 the poor had run out of food, but Hatto, having all the grain stored up in his barns, used his monopoly to sell it at such high prices that most could not afford it.
The "Mouse Tower" story about a cruel overlord has been told about numerous rulers, this being the most famous version, although there is no historical evidence for it.
In addition to being immortalized in the above poem by Robert Southey, an allusion to this tale can be found in "The Children's Hour" by Henry Wadsworth Longfellow: The legend of Bishop Hatto and his Mouse Tower is also referenced in the 1812 children's novel, "Swiss Family Robinson" by Johann Wyss.