After her husband's death, Mary ruled as
regent for their son
James III of Scotland until her own death three years later. Mary was drawn into the
Wars of the Roses taking place in England at this time. She appointed
Bishop James Kennedy as her chief advisor; their companionship was described as well-functioning despite the fact that the bishop favoured an alliance with the
Lancastrians, while Mary at first wanted to continue playing off the warring parties in England against each other. While Mary was still mourning the death of her husband, the English queen of the
House of Lancaster,
Margaret of Anjou, fled north across the border seeking refuge from the Yorkists. Mary sympathetically aided Margaret and took
Edward of Westminster into her household to keep them out of Yorkist hands. Mary's dealings with Margaret were mainly to provide aid to the deposed queen. Mary gave a number of Scottish troops to help Margaret and the Lancastrian cause. Mary and Margaret also organised a betrothal between Margaret's son,
Edward, and Mary's daughter Margaret in 1461. In return for her support, Mary asked for the town of
Berwick on the Anglo-Scottish border, which Margaret was willing to give up. Relations between the two women deteriorated, however, with the increasingly friendly alliance between King
Edward IV of England and Duke Philip of Burgundy. Any support by Mary for Margaret, Edward IV's enemy, threatened the alliance that Philip wanted with Edward IV against King
Louis XI of France. Edward IV tried to put a stop to Mary's support of Margaret by proposing marriage to the widowed queen, which Mary rejected. Mary's uncle, Duke Philip, pressured her to call off the betrothal of her daughter and Margaret's son, to Margaret's disappointment. In 1462, she paid the Lancastrian royals to leave Scotland and made peace with Edward IV. She also hinted at the possibility of a marriage between herself and the new English king. Mary, reportedly, had several affairs during her period as regent, notably one with the Lord Hailes, although some recent historians have cast doubt on these claims. Mary went ahead with James II's plan to build a castle on land at
Ravenscraig, designed to withstand the use of artillery, and lived in it while it was under construction until her death.
Trinity College Church Mary founded
Trinity College Church c. 1460 in memory of her husband. The first reinterment was in the royal vault; the second, near the entrance.
Daniel Wilson disputed Laing's theories and maintained that the first reburial was indeed that of Mary of Guelders. Wilson noted that since Mary died before the building of the
collegiate church was finished, her obsequies had been held at
Brechin Cathedral before the burial at Trinity College Church. ==Issue==