Editor's Note: This article is one of two sidebars to "Give Your Pedigree the Royal Treatment: Researching Noble Lines" by Eugene A. Stratton, FASG. See also "Comments on Royal Descent."

When most Americans hear the word "queen" these days, they immediately think of Queen Elizabeth II of England, whose lengthy reign and media-hounded royal family make newspaper headlines all over the world daily. But Queen Elizabeth is not the world’s only current, reigning queen—she’s not even the only queen in Europe.

Currently, three queens reign in Europe, and a fourth is close to the throne. The four are: Elizabeth of the House of Windsor, Queen of the United Kingdom; Margaret of the House of Holstein-Glucksburg, Queen of Denmark; Beatrix of the House of Orange-Nassau, Queen of the Netherlands; and Victoria, the crown princess of Sweden, who will inherit the country’s throne upon her father’s death. Historically, this is a unique circumstance, but even more unique is the fact that they are all related.

The "millennium queens" trace their ancestry through three notable, sixteenth-century queens: Elizabeth Tudor of England; Mary of Guise, Dowager Queen Consort of Scotland; and Mary, Queen of Scots. All four are also descendants of Christian I, a fifteenth-century king of Denmark, Norway, and Sweden. And the four all begin to trace their ancestry through King George II of England. Coincidence? Hardly. It all comes from the last millennium’s frequent, political marriages between European monarchs. But the event, in its uniqueness, is certainly remarkable.

And if that connection is not enough for royalty aficionados, also of note is the fact that both English queens to bear the name of Elizabeth have succeeded to the throne at the comparatively early age of twenty-five. Elizabeth I was born in 1533 and gained the throne in 1558; Elizabeth II, born in 1926, succeeded in 1952, just before her twenty-sixth birthday.

To read more about the millennium queens and their ancestry, and to trace their lineages through historical figures of note, read Stephen Ash’s article "Millennium Queens", from which this sidebar has been abstracted.