That the government considered it possible that Prince Charles might one day want to marry Princess Marie-Astrid is shown by the fact that there were several committees set-up to see if it was constitutionally possible to repeal the ban on British royals marrying Catholics. There was soft opposition, from the beginning, including from Charles's beloved grandmother, Queen Elizabeth the Queen Mother, who was not only a devout Protestant but was also naturally opposed to change. Concerns about how such a marriage would affect the already-volatile situation in Northern Ireland were also voiced. Early in 1980, the Prime Minister, Margaret Thatcher, set up a small committee to discuss the issue. According to her future biographer, Hugo Young, the Prime Minister herself was strongly opposed to changing the law or to encouraging the Prince's marriage to Marie-Astrid. And her objections rested squarely on the idea that the princess's religion was problematic and undesirable. Some of the committees other members later told Young that they had been shocked by "the extreme anti-Catholicism" of the Prime Minister.
Eventually the rumours about Charles and Marie-Astrid faded away. Maybe that's all they ever were. Neither Charles, nor Marie-Astrid, ever went firmly on the record about how much truth there had been in the idea that they could quite married. Evidently, Mrs. Thatcher considered it a possibility, but we don't know how sold on the idea Charles himself ever was. Charles soon announced his forthcoming marriage to the beautiful Diana Spencer - young, virginal, British, aristocrat and Protestant. And Marie-Astrid married a member of the deposed Austrian royal family, Archduke Carl-Christian, in 1982. (Read entire post)