The House of Leiningen was very involved in The Order of Saint Joachim. Not only were they members of the Order, three ruling Counts of Leiningen-Neuleiningen served as Grand Masters of The Order of Saint Joachim:

  • George Karl I August Ludwig (1717-1787)
  • Karl II Gustav Reinhard Waldemar (1747-1798)
  • Ferdinand Karl III (1767-1813)

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 the third hereditary ruler of the Grafschaft of Leiningen - Westerburg - Neuleiningen to serve as Grand Master of the Order of Saint Joachim. 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 own death in 1813.

Georg Karl I August Ludwig ruled Leiningen - Westerburg - Neuleiningen from 1726 until his death in 1787. He was The Order of Saint Joachim's third Grand Master (1784 to 1787) following the death of Graf von Monfort. 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. At right is his portrait wearing the breast star of The Order of Saint Joachim (bottom star) and possibly the dark green cordon or sash ribbon of a Grand Cross under his coat. 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 the fifth 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. His lands were incorporated into the Grand Duchy of the Berg and given to Napolean's brother-in-law, Marshal Joachim Murat, who not only took over his lands in 1806 but proclaimed himself the new Grand Master of the Order of Saint Joachim and awarded the Order to many of his French military friends.

The Order under the Leinigens never recognized Murat as the Order's Grand Master, who appears to have lost interest in it shortly after Murat was made King of Naples by Napoleon two years later in 1808. Murat awarded The Order of Saint Joachim in the interim to many of his fellow French calvary and other officers. Interestingly, after the restoration of the French monarchy following the final defeat of Napoleon, many French generals successfully petitioned Louis XVIII for permission to continue to wear The Order of Saint Joachim among their decorations after 1815. 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.

His Majesty Leopold II, King of Hungary and Bohemia formally acknowledged and sanctioned the wearing of the insignia of the Order of Saint Joachim on May 23, 1790 with a document of Royal Concession. A few months later he was crowned Emperor of the Holy Roman Empire, succeeding his brother Joseph II. One of his first acts was to appoint Graf Christian von Leiningen, a knight of The Order of Saint Joachim and relative of the Grand Master, to be his Chamberlain of the Imperial Palace..

The Leinigens were closely related to and intermarried with the Sachen Coburgs. 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.

Numerous member of the Leiningen were members of the Order of Saint Joachim, as shown in contemporary Order records, including Amalie Leopoldine, Countess zu Leiningen, who became a member in 1787 and became a Dame Grand Cross in 1794.