The Legend of Popiel

From Wikipedia:

"As the legend goes, Prince Popiel ІІ was a cruel and corrupt ruler who cared only for wine, women, and song. He was greatly influenced by his wife, a beautiful, but power-hungry German princess. Due to Popiel's misrule and his failure to defend the land from marauding Vikings, his twelve uncles conspired to depose him; however, at his wife's instigation, he had them all poisoned during a feast (she might have done it herself). Instead of cremating their bodies, as was the custom, he had them cast into Lake Gopło.

When the commoners saw what Popiel ІІ and his wife had done, they rebelled against their rulers. The princely couple took refuge in a tower near the lake. As the story goes, a throng of mice and rats (which had been feeding on the unburnt bodies of Popiel's uncles) rushed into the tower, chewed through the walls, and devoured Popiel and his wife alive. Prince Popiel was succeeded by Piast Kolodziej and Siemowit."