At the siege of Vienna, in 1485, he frequently walked all around the walls, unattended, or, at most, followed by a page. On one occasion, he stole into the city in disguise. Dressed in the shabby dress of a country boor, with a basket containing butter and eggs on his back, he traversed the city in every direction, selling his wares, and at the same time spying out the condition of the fortifications. He lounged about in the market-place, listening to what the people talked about, and what they were planning. He made his escape in safety, and, making good use of what he had seen and heard, the city shortly afterward fell into his hands. Upon another occasion, his forces being stationed opposite the Turkish camp, he assumed the disguise of a Turk, and mixing with the country people who entered the camp to sell their provisions, he succeeded in passing in with them. Once there, he had the hardihood to seek out the sultan’s tent, and, settling down near it, he went on selling provisions and spying all day long. Upon his return to the Hungarian camp, he sent, on the following day, a letter to the sultan, conceived in these terms: “Thou guardest thy camp badly, emperor, and thou art thyself badly guarded. For yesterday I sat, even from morn until night, near thy tent, selling provisions. And lest thou doubtest my words, I will tell thee now what was served on thy table.” The sultan, upon reading this letter, became frightened, and, together with his army, noiselessly left the neighborhood. The king was particularly rigorous in the ordering of the sentry service. He used to rise at night and inspect the sentinels, to see if they were awake, and in their places. He was especially active during sieges, being constantly on his feet. He was never satisfied with reports alone, but was bound to look after every thing in person. Everybody marvelled at his incessant watchfulness. He awoke at the slightest sound, at the merest whisper. At the same time, he was famed for his sound slumbers amidst the din of battle. Upon such occasions, the shouts of the men, the roaring of the cannon, and the reports of the musketry seemed to lull him to sleep. [Illustration: FORTRESS OF BUDA.]