This Supreme Court case involved William Parsons, the plaintiff in error, and Bedford, Breedlove, and Robeson (the defendants). The dispute arose from a contract between Parsons and the defendants for the sale of land. According to this agreement, Parsons was to pay $1 per acre for certain tracts of land located in Georgia. However, when it came time to make payment on these lands he refused due to his belief that they were not worth more than 50 cents an acre. As such he argued that he should only be required to pay half of what was agreed upon in their original contract. In response the defendants sued him for breach of contract but lost at trial court level as well as on appeal before reaching the Supreme Court where they ultimately prevailed with Chief Justice Marshall ruling against Parson's argument stating that "a party cannot set up his own mistake or ignorance as a defence". This decision established precedent which still stands today; parties are bound by contracts regardless if one side is unaware or misinformed about its terms or conditions prior to signing them into effect.

In the case of William Parsons vs. Bedford, Breedlove, and Robeson, the dissenting opinion argued that a contract between two parties should be enforced as written unless there is evidence of fraud or mistake. The majority held that an oral agreement to extend payment terms was binding even though it contradicted a prior written agreement between the parties. The dissent disagreed with this interpretation because they felt that contracts must be interpreted according to their plain language and not by what one party may have said in passing during negotiations. Furthermore, if such agreements were allowed then any verbal promise could override a previously agreed upon contract regardless of its validity or enforceability under state law. As such, the dissent concluded that allowing oral modifications would lead to uncertainty in contractual relations which could ultimately harm both contracting parties and society at large by creating an environment where promises are not taken seriously due to lack of enforcement mechanisms for them