The statute that declared Edward IV’s marriage invalid and his children illegitimate was Titulus Regius.
Passed by the Parliament of England in 1484, Titulus Regius (“royal title” in Latin) confirmed Richard III’s claim to the throne. It endorsed the argument that Edward IV’s marriage to Elizabeth Woodville was invalid because Edward had allegedly already entered a marriage precontract with Lady Eleanor Butler, who was still alive.
The statute therefore treated Edward and Elizabeth’s children—including Edward V, Richard of Shrewsbury, and Elizabeth of York—as illegitimate and excluded from succession. Richard, Duke of Gloucester, was presented as the next legitimate heir and became Richard III in 1483.
The statute was politically explosive. After Henry VII defeated Richard III at Bosworth Field in 1485, Henry ordered Titulus Regius repealed and its copies destroyed. This helped remove a legal obstacle to his marriage to Elizabeth of York, one of the children whom the act had declared illegitimate. The act’s surviving text is consequently an important source for the political case made against Edward IV’s heirs.