In 1449 or 1450, Eleanor married Sir Thomas Butler (son of Ralph Butler, Lord Sudeley), who died some time before March 1461. In the political turmoil surrounding the change of monarchs then, the widowed Eleanor's father-in-law took back one of the two manors he had settled on her and her husband when they married, but he did not complete the required paperwork by obtaining a licence for the transfer of title, and the new king, Edward IV, seized both the properties.
The exact course of events is uncertain, but it seems that Lady Eleanor went directly to King Edward to ask him to return her property. Edward (who, though barely out of his teens, already had a reputation for womanizing) was more interested in her than in her property. It is said that Edward made a legally binding contract to marry her. According to the French political analyst, Philippe de Commines, the priest who later came forward and testified to having performed the ceremony was Robert Stillington, Bishop of Bath and Wells. Edward married Elizabeth Woodville in 1464, and it was later suggested that one reason the marriage was not announced publicly was the danger that Eleanor would come forward with the news of her earlier marriage to the king. Robert Stillington rose to be Chancellor of England, along with other lucrative posts.
Lady Eleanor Butler died in a convent in June 1468 and was buried in the Church of the White Carmelites, Norwich, England. Some years later, the priest in question (Commynes is the only source who identifies him as Stillington) is said to have told King Edward's unstable and untrustworthy brother, George, Duke of Clarence, about the pre-contract. Clarence was already on the verge of rebellion against his elder brother; Edward now threw both his brother and Stillington into the Tower of London. Clarence was tried before Parliament (with Edward himself as his accuser) in January 1478, convicted of treason, and sentenced to be executed.
There has been speculation that the reason Clarence was killed privately in the Tower ( whether he was really drowned in a "butt of Malmsey" wine or not) may have been that Edward wanted to ensure that he did not have an opportunity to disclose in public the secret that would make his brother's children illegitimate and himself the next in line for the throne. Stillington's imprisonment was to be a warning. Only after Edward's death did he come forward publicly with that evidence, this time offering it to the future Richard III of England, to prevent Edward IV's son from being crowned as Edward V. Richard then took the throne.
No records survive of the meeting of the Parliamentary lords on June 9, 1483, where Stillington is said to have presented the evidence of the pre-contract, including documents and other witnesses. The Duke of Buckingham is supposed to have told Morton afterwards that he had believed that evidence when he saw it but had later changed his mind. When Henry VII of England came to the throne, he ordered all documents relating to the case to be destroyed, as well as the act of parliament by which Richard was enabled to claim the throne; so efficiently were his orders carried out that only one copy of Titulus Regius has ever been found.
After Richard's death, Tudor "historians" -- including Sir Thomas More in his History of Richard III -- named Elizabeth Lucy as the woman Stillington testified he had married to Edward. Elizabeth Lucy (who may also have been called Elizabeth Wayte) was probably the mother of Edward IV's bastard son Arthur (Plantagenet), Viscount Lisle (1461-1542). (Arthur was imprisoned in the Tower of London in 1540 on charges of plotting to betray Calais to the French; when the verdict came in acquitting him, he had a heart attack and died.)