In the meanwhile Frederick had been inveigled into another maritime adventure, which was to prove just as barren of positive results. Early in the war several Englishmen communicated to the King their readiness to fit out privateers to prey on the commerce of Austria and Sweden, both of which countries had seized Prussian merchantmen. They protested in all cases that their principal motive was a desire to serve the cause of a monarch whom they admired and revered, and who was, as a matter of fact, at that time the ally of England. But at the same time they promised him "prodigious profits" from the enterprise, and it was admittedly the latter consideration which induced the King to listen to their proposals. Though his own Ministers expressed strong doubts, and the English Government urged that he would run the risk of embroiling himself with neutral States, he issued a number of letters of marque. The advice which had been given him proved to have been only too well founded. Not only were there no "prodigious profits," but the blunders of the royal officials and the indiscretions of the ships under his flag involved the King in voluminous diplomatic correspondence and long and fruitless litigation. To accelerate the process of destroying the enemy's trade, a number of blank letters of marque, ministerially signed and stamped with the royal seal, were sent out to the Prussian Minister in London, and he somewhat imprudently lent a couple of these to an interesting adventurer, named Erskine Douglas, who said that he wished to show them to shipowners with whom he was in treaty for the equipment of privateers. Douglas claimed to be a relative of the Prussian Field-Marshal Keith, who was of Scottish origin, and he brought letters of introduction from well-known members of the English nobility, so the Minister may perhaps be excused for entrusting the documents to him. But his confidence was gravely abused, for Douglas, having come to an agreement with the firm of Dunbar and Eyre, filled in the forms on his own responsibility, and two privateers were sent out with these fraudulent credentials.