Walter Hinteler wrote:Which, then, is e.g. a great source for historians (the study of old library records is certainly a kind of historical auxillary science).
There are several copies of the Anglo-Saxon chronicles, although few complete ones. One of the complete copies is in the British Museum. Exactly such a thing occured, and became a "fact" of history.
One of the Earls of Wessex, commonly known as "Kings," was Aethelred. This comes from
aethal (sorry, can't do anglo-saxon letters on this keyboard) meaning noble, and
rede, meaning counsel. Aethelred was a train wreck of a King. He gave away the entire candy store to his sycophantic hangers-on within a year of succeeding to the dignity. Therefore, his people named him Aethelred Unrede--Aethelred the Ill-Counseled, or Ill-Advised.
Centuries pass. While that copy was still a dusty tome in some Oxbridge library, at some point in the late 15th or early 16th century, some wit of a gnomish scholar wrote in the margin "Ethelred the Unready." The joke was apparent to all anglo-saxon scholars, and coughing up dusty little laughs among themselves, they retailed the joke for a few more centuries--to the point now that even sincere university instructors in history name Aethelred Unrede as Ethelred the Unready, and go through ludicrous contortions of explanation for why he was named "Unready."
EDIT: I have it on good authority that the author of that unseemly witticisim now owes library fines in excess of the annual gross domestic product of the United Kingdom.