These apprehensions on the part of the monarch and his court were due to an incident which took place on the night of April 24, 1898, and which was of sufficient importance to be comprised in the regular report made on the following morning to his military superiors by the officer of the guard at the Hofburg. It seems that the sentinel posted in the corridor or hall leading to the chapel was startled almost out of his senses by seeing the form of a white-clad woman approaching him, soon after one o'clock in the morning. He at once challenged her, whereupon the figure turned round, and passed back into the chapel, where the soldier then observed a light. Hastily summoning assistance, a strict search was instituted, but the chapel was explored without any result. The sentinel in question was a stolid, rather dull-minded Styrian peasant, who was possessed of but little power of imagination or of education, and who was entirely ignorant, therefore, of the tradition according to which a woman in white makes her appearance by night in the Hofburg at Vienna, either in the chapel or in the adjoining corridors and halls, whenever any misfortune is about to overtake the imperial house of Hapsburg. On each occasion, this spectral appearance to the sentinel on duty has been described in the report of the officer of the guard on the following morning, and is absolutely a matter of official record. The previous visitations of the "white lady" had taken place on the eve of the shocking tragedy of Mayerling; a few weeks previous to the shooting of Emperor Maximilian of Mexico; and prior to the burning to death of the daughter of old Archduke Albert, at Schoenbrunn; while the very fact that there should have been no supernatural appearance of this kind at the time when Archduke John vanished from human ken, leads the imperial family and the Court of Austria to still doubt the story, according to which he perished at sea while on his way round Cape Horn, from La Plata to Valparaiso. I do not know the origin of the "white lady" tradition at Vienna, nor have I ever been able to ascertain anything definite about her history, but there is plenty of documentary evidence, as well as a wonderful array of records concerning "the white lady of the Hohenzollerns," who makes her appearance in the old palace at Berlin whenever death is about to overtake a member of the reigning house of Prussia. The late Emperor Frederick--the most matter-of-fact and least imaginative prince of his line--was particularly interested in the matter, and collected all the evidence that he could upon the subject, for the purpose of depositing it in the archives of his family. Perhaps the most important testimony in this connection are the sworn statements signed by Prince Frederick of Prussia, and a number of his fellow officers, to all of whom the "White Lady" is declared to have appeared as they sat together on the eve of the prince's death at the battle of Saalfeld in 1806.