This is Bernharður Guðmundsson, he droped by at the Old bookstore to day. His grandfather was a farmer in Önundarfjörður and was a regular customer in the Bookstore back in the days.
While looking up his grandfather purchase history, we found out that in the year 1919, he owed the Bookstore 1,500kr.
His grandson decided to paid his debt today, 100 years later.
Thanks for the business!