Margarethe (Grethe) joined the US Army and after graduating from college, served seven years on active duty and married a fellow military officer.

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When military regulations changed in 1972 and women were allowed to serve in the military with dependents, Margarethe returned to the Army Reserves.

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The appointment is a case study in the right way to manage transition at the top, says Margarethe Wiersema, an expert in management succession at Rice University.

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Queen Margarethe of Denmark, Crown Prince Alexander of Serbia and Princess Katherine, the Grand Duke and Duchess of Luxembourg, King Harald of Norway and Queen Sonia also attended.

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