Among the many French soldiers who entered Swedish service during the Great Northern War few acquired the reputation of Jean Charles de Folard (perhaps better known as Chevalier de Folard). His letters to Goertz form the basis for chapter IX in Charles de Coynard biographic study (1914). Folard greatly admired Charles XII and went to Sweden in 1716. An illness forced him to return to France in the autumn of 1717, but the ship he was travelling on was wrecked off Skagen. In Folard's company was Hans Gyllenskepp, who was carrying secret dispatches for Poniatowski. Folard lost most of his luggage, including manuscripts and letters, but survived and got back to France. He was still planning to return to Sweden when Charles fell in November 1718.
What Coynard did not know was that some letters from Folard to Charles remain, well hidden in a private archive. They suggest that Folard and Charles had immersed themselves in discussions about ancient history as well as about more practical matters. On 23 June 1718 Folard writes to the King that he has sent a drawing of a gun carriage for naval use and has been working on similar inventions for field and siege artillery. Due to the risk of them being captured by the enemy he has not yet forwarded those plans, but will do so if the King requests it. He also writes about a rifle which will fire five shots in the time an ordinary musket fires one.
The second surviving letter is dated Paris 28 August 1718. Folard discusses at some length the reasons behind Alexander's great success against the Persians and the exploits of Caesar. Folard seems to suggest that these ancient examples proves that a smaller force can succeed by a rapid and determined assault (something Charles undoubtedly fully agreed with).