Count Ferdinand Karl III, ruler of the Leiningen - Westerburg - Neuleiningen, was the Grand Master of the Order when the the Cross of a Knight Grand Commander of The Order of Saint Joachim was awarded to Admiral Lord Nelson for his victory over the French forces of Napoleon at the Battle of the Nile. 

Count Ferdinand Karl III was born in 1767 and died in 1813. He succeeded his father as ruler of Leiningen - Westerburg - Neuleiningen in 1798 and ruled until his death in 1813.

Count Ferdinand Karl III was the third hereditary ruler of the Grafschaft of Leiningen - Westerburg - Neuleiningen to serve as Grand Master of the Order of Saint Joachim. Georg Karl I August Ludwig ruled Leiningen - Westerburg - Neuleiningen from 1726 until his death in 1787. Following the death of Graf von Monfort, he served as Grand Master of the Order from 1780 to 1787. He was followed by his son Karl II Gustav Reinhard Waldemar, who ruled from 1787 to 1798. He was in fact taken prisoner and robbed of his estates by the invading French armies in 1793. On his death in French captivity in St. Germain in 1798, his son Count Ferdinand Karl III became the hereditary ruler of Leiningen - Westerburg - Neuleiningen and Grand Master of the Order of Saint Joachim. 

Being close to the French border, Leiningen - Westerburg - Neuleiningen was invaded by Napoleon's army during his war on the German states. As France was the mutual enemy of Leiningen - Westerburg - Neuleiningen and England, this at least partially explains the decision of The Order of Saint Joachim to confer the Cross of a Knight Grand Commander of the Order on Admiral Lord Nelson for having handed Napoleon a decisive defeat at the Battle of the Nile.

The British Royal Family also has a relationship by marriage to the Leiningen family. Edward, Duke of Kent (1767-1820) the fourth son of George III, was born at Buckingham Palace, London. In 1818 he married Princess Victoria Mary Louisa (1786-1861), daughter of the Duke of Saxe-Coburg-Saalfeld, and widow of the Prince of Leiningen. For the sake of economy they lived at Leiningen, and went to England (1819) for the birth of their child, the Princess Victoria. Edward's three elder brothers, George IV, the Duke of York, and William IV, died leaving no children and Princess Victoria succeeded to the throne as Queen Victoria of England in 1837.

As shown on the map, Leiningen - Westerburg was located on the southern borders of Hesse and Bavaria.