Plans were hatched during World War II to use the future queen to counteract growing Welsh nationalist discontent.
Officials wanted the royals linked to Wales
A secret file has revealed that there was growing concern over the influence of Plaid Cymru - especially in north Wales.
One suggestion was to affiliate the then teenage Princess Elizabeth to the Urdd as a way of diffusing tensions.
Details of the plan were discovered in documents just released under the Freedom of Information Act.
The files were stored at the National Archives in Kew and held under a 100-year embargo.
A memorandum submitted to the then Home Secretary Herbert Morrison by constitutional expert Edward Iwi claimed that there was a real danger of Welsh nationalists siding with Irish nationalists.
To counter the threat of such a "hostile movement", Iwi proposed making the then Princess Elizabeth - now Queen Elizabeth II - the Constable of Caernarvon Castle. The post was held at the time by Lloyd George.
The idea was that every time there was a threat to national unity, a royal figure would be rolled out to smooth things over.
The idea was rejected by the home secretary over fears it would stir up tensions between north and south Wales.
Lloyd George's title was to be give to the princess
But Morrison did take forward another plan which would have seen the young princess being made patron of the Welsh League of Youth or Urdd Gobaith Cymru.
This, he believed, would be "of great value in improving permanently the relations between the two countries".
Morrison also planned for her to tour Wales on behalf of the Urdd - a ceremonial gesture which he hoped would have "a deep and lasting effect" on the youth of Wales.
This plan delighted the Welsh establishment - not least the Urdd's founder, Syr Ifan ab Owen Edwards.
However, neither plan succeeded. King George VI came to the conclusion that no tour should be undertaken because of the pressure that would put on the princess.
More controversially, the plan to make Princess Elizabeth the Urdd's patron was also dropped following the King's concerns that two of the Urdd's most prominent leaders were conscientious objectors - a view shared by the princess herself.
Support for the monarchy
Eventually, plans to formally link the royal family with Wales were dropped. But when the investiture of Prince Charles as Prince of Wales took place in 1969, critics suggested it was a gesture to kill off Welsh nationalism.
Historian Dr John Davies told BBC Wales there was, indeed, support for the monarchy in Wales at the time when the home secretary was considering developing a close relationship between Wales and the future queen.
"I think there was a strong royalist feeling in Wales," he said. "Saunders Lewis, who was president of Plaid Cymru in the 1920s and 1930s declared himself a strong royalist."
Dr Daviespointed out, however, that there would have been problems developing a close relationship between the future queen and the Urdd.
"Several of the leaders of the Urdd were declared pacifists," he explained. "So it might have been rather awkward in 1940/41 for the heiress to the throne to have been closely involved with a movement that was not 100% in favour of Britain's role in the war."