The last great achievement of his military career was commanding the Prussian troops to victory over the Saxons at the Battle of Kesselsdorf in 1745 during the Second Silesian War.

He remained in the field to the end of the war of 1697, the affairs of the principality being managed chiefly by his mother, the Dowager Princess Henriette Katharina (in fact, she had been acting as regent since the death of his father until he reached adulthood the same year, but continued in charge of the government of Anhalt-Dessau for some time after he attained his majority).

In the campaign of 1704 the Prussian contingent served first under Louis William, Margrave of Baden-Baden, then Prince Eugene of Savoy, and fought at Blenheim.

In 1710 Leopold succeeded to the command of the entire Prussian contingent at the French front, and in 1712, he was made a field marshal at the particular request of the crown prince of Prussia, Frederick William, who had served with him as a volunteer.

Shortly before this he had executed a coup de main on the castle of Moers, which had been held by the Dutch in defiance of the claims of the Prussian king to its possession.

In peacetime, and especially after a court quarrel and duel with General Friedrich Wilhelm von Grumbkow in 1725, he devoted himself to the training of the Prussian army.

Thus Leopold, with the steadfast support of King Frederick William I of Prussia, himself one of the greatest drillmasters of Europe, turned to good account the twenty years following the peace with Sweden.

During this time two incidents in his career deserve special mention: firstly, his intervention in the case of the crown prince Frederick, who was court-martialed for desertion, but due to his efforts reinstated in the Prussian army; and secondly, his successful role in the War of the Polish Succession on the Rhine, where he served under his old chief Eugene of Savoy and held the office of Field Marshal of the Empire.

The king, indeed, found Leopold somewhat difficult to manage, and the prince spent most of the campaigning years up to 1745 in command of an army of observation on the Saxon frontier.

A combined effort of the Austrians and Saxons to retrieve the disasters of the summer by a winter campaign towards Berlin itself led to a hurried concentration of the Prussians.

One year after officially becoming an adult in 1697, he married his beloved Anna Louise in Dessau on 8 September 1698, forming a union that was morganatic until the imperial decree of 29 December 1701.

[1] Leopold and Anna Louise enjoyed a long and happy marriage, and the princess acquired an influence over her husband that she never ceased to exert on behalf of his subjects.