We can take the medieval Europe for reference as a time period. I sometimes wondered whether this could have been a possibility when I see large corporations poaching on each other's CEOs or similar leaderships.
There is the situation of Jean-Baptiste Bernadotte, who rose rapidly through the ranks of the French Army in the 1790s. On May 19th 1804 he was promoted to the rank of Marshall and did very well at the battle of Ulm in 1805, He did not do so well at the battle of Auerstadt in 1806 and was lightly wounded at the battle of Friedland in 1807. Napoleon did nothing to stop him from accepting an offer from the Swedish government in 1810, On August 21 1810 he became the crown prince of Sweden. He was in charge of Sweden's foreign affairs and had Sweden join the Sixth coalition to fight Napoleon in 1813, He became king of Sweden on 2/5/1818 and his direct descendent is still the king of Sweden in 2014.
Bernadotte was one of just 26 Marshals of France during the Napoleonic wars, but it is questionable how exceptionally well he performed. Most historians rate the Marshalls Davout, Soult, Lannes and Massena as better generals and Bernadotte does not really stand out to much from the other 21 Marshals of France.