An account of Beethoven being lost in his creative world:

Thayer tells us of a conversation he had with a Professor Blasius Höfel, a teacher of fine arts at Weiner Neustadt, a little town near Vienna.  one evening, Höfel was in a tavern with some of his colleagues, the Commissioner of Police being a member of the party.  A constable appeared and said to the commissioner, “we have arrested somebody who will give us no peace.  He keeps on yelling that he is Beethoven; but he surely is a tramp.  He has no hat, wears an old coat, and has nothing on him by which he can be identified.”  The commissioner, perhaps unwilling to have his convivial evening spoiled by so trifling an incident, told the constable to keep the man under arrest until morning and he would then investigate the matter.  At eleven o’clock that night commissioner was awakened by a policeman with the information that the prisoner insisted that the musical director of the Wiener Neustadt, a man by the name of Herzog, be called to identify him.  Troubled now, the commissioner got up, dressed, went out, woke up Herzog, and both men went to the jail.  As soon as Herzog saw the man, he exclaimed, “That is Beethoven!”  Herzog took him home, gave him his best room, and the next day the mayor of the town came, falling over himself with profuse apologies.

Cited in: Marek, George (1969) Beethoven: Biography of Genius. London: William Kimber, p. 564-565