Prince_Augustus_William_of_Prussia--William,_German_Crown_Prince

Prince Augustus William of Prussia (German: August Wilhelm; 9 August 1722 – 12 June 1758) was the son of King Frederick William I of Prussia and a younger brother and general of Frederick the Great.
Augustus was the second surviving son of Frederick William I and Sophia Dorothea. His older siblings included Wilhelmina (later Margravine of Bayreuth), Frederick II (later King of Prussia), Friedrike Louise (later Margravine of Ansbach) and Louisa Ulrika (later Queen consort of Sweden).
Augustus was favored by his father over Frederick and was popular at the Prussian court. When his brother Frederick became king in 1740, Augustus became heir presumptive and moved into Fredrick's former residence, the Crown Prince's Palace in Berlin. When his older sister Louisa Ulrika married the King of Sweden in 1744, she founded the Ordre de l'Harmonie, of which Augustus was one of the first recipients.
Augustus served his brother as a general in the War of the Austrian Succession and distinguished himself in the Battle of Hohenfriedberg. But in the Seven Years' War, owing to the fatal retreat of Zittau during the Battle of Kolin in 1757, he incurred the wrath of his brother the King, and withdrew from the army. This conflict between the two brothers led to a correspondence, which was published in 1769.