One of the most famous cows in all of history is Rose 2d of Aberlone, who lived right here in Michigan. Rose belonged to Hiram Walker (yes, that Hiram Walker) who, in addition to distilling spirits, bred cattle. In 1887, Mr. Walker contracted to sell Rose, who was believed to be barren, to Theodore Sherwood of Plymouth, Michigan.
When Mr. Walker received the unexpected news that Rose was pregnant, he refused to let her go, and an historic legal battle ensued. (Not surprisingly, Mr. Sherwood only wanted to pay the contracted price of $80. Mr. Walker, on the other hand, felt he should instead be paid the going rate for a fertile cow, which was ten times $80.)
This entertaining case not only made it all the way to the Michigan Supreme Court, it became the seminal case establishing the important legal doctrine of mutual mistake and is still studied by every law student across the country.
The doctrine of mutual mistake allows a party to rescind a contract if both parties are mistaken about key facts relating to their deal. The application of this new doctrine not only enabled Hiram Walker to cancel his contract and keep his cow, it reshaped contract law and caused Rose to be memorialized for all time in both prose and poetry.