HELSINKI, Finland (AFP) — A book borrowed from a Helsinki library was returned in May — 84 years overdue, a librarian told AFP on Wednesday.

A Finnish translation of Sir Arthur Conan Doyle’s book “Refugees” was received by librarian Heini Strand on Monday at the main desk at the Helsinki Central Library Oodi.

“The due date of the loan was December 26, 1939”, Strand said, adding that she had never received a book so long overdue.

The relationship between the person who happily returned the book and the original borrower remained unknown.

“Usually these kinds of loans returned decades after the due date are books found when people go through deceased relatives’ belongings,” Strand said.

“People want to do the right thing and return the book that is the library’s property…I think that is lovely”, she added.

A likely explanation for the delayed return was that the due date fell a month after the Soviet Union’s invasion of Finland in November 1939, Strand noted.

“The return of the book might not have been the first thing on the borrower’s mind when the due date approached”.

The so-called Winter War between Finland and the Soviet Union raged between the neighbouring countries until March 1940, when a peace treaty was signed forcing Finland to make significant land cessions.

“If the person survived the war, the person probably had other things on their mind than returning the book”, Strand said.

The book is a historical novel published in 1893 and set in 17th century France, written by the British author best known for his stories about the character Sherlock Holmes.

According to Strand, the library may make the book — an edition published in 1925 — available to the public again since it was received in such good condition.

“The quality of old books is usually much better than new ones”.