In the summer of 1805 that opportunity presented itself in the form of a letter which was addressed to him from one Karl Schulmeister, who, like many well-educated Alsatians, spoke and wrote French and German equally well. The writer in the course of a lengthy communication informed the Field-Marshal that he had been removed across the French frontier by Napoleon's orders, on the ground that he was an Austrian spy. Schulmeister admitted the facts. He had been moved, he wrote, out of pure love of his country and hatred of Napoleon, to act the spy through the imperial armies of France, as to the equipment, plans, intentions and organisation of which he was perfectly well acquainted. All this information he was willing to give up on the condition of being allowed to serve on the staff of the Austrian army. Then followed an account of his Hungarian ancestry and many other details which need not be particularised here. It is sufficient to say that Mack eagerly seized the opportunity of possessing himself of the services of a man who knew all about the French army, and engaged him as secret-service agent on his own particular account. The spy, who had visited Vienna in order to meet the Field-Marshal, was furthermore given military rank, and Mack procured him—on the ground of his noble Hungarian descent, with forged attestations as to which Napoleon's agents had supplied him at his own request—membership of some of the most exclusive military clubs in the Austrian capital. As his supply of money, coming as it did from Napoleon's long purse, was practically unlimited, Schulmeister, the ex-smuggler and actual spy, became an easy favourite in some of the most exclusive circles in the proudest society in Europe.