From 1755 to 1761 Oglethorpe was out of England. Very little is known about what he did over these six years; they are referred to as his "missing years". On 22 September, he had unsuccessfully petitioned George III to reactivate his Georgia regiment, and by 9 December Oglethorpe had left England and arrived in Rotterdam. There he requested a position in the military of Prussia from his friend James Francis Edward Keith, whom Oglethorpe had fought with in the 1710s. There are no records of what happened to Oglethorpe in the five years after he wrote a letter to Keith on 3 May 1756. Boswell wrote that he "went abroad in 1756 to his freind Keith [...] fought in the army" and "was with Keith when killed". Baine concludes that Oglethorpe took the pseudonym 'John Tebay' and likely joined the Prussian army in mid to late 1756. He was likely with Keith and Frederick the Great during the campaigns of the Seven Years' War. He probably left the army to visit family over part of the winter. In early 1758 Oglethorpe was almost discovered by Joseph Yorke, an Englishman. He was wounded at a battle on 14 October. Keith reportedly fell into Oglethorpe's arms when he was killed at the Battle of Hochkirch. He left the army in March 1759 and had returned to England by October 1761.