This annotation describes how a small scribal error in a late medieval Danish document led to that document being left out of the later printed source edition, because the scribe’s correction of his own mistake was not recognized by the man who registered the document later on in the city archives in Copenhagen. It talks about how this sealed the fate that the document remained unknown and unpublished until a registration project at Copenhagen City Archives rediscovered and redated it in 2017 finally resulting in the making of the first-ever printed source edition in 2019. It also discusses the implications this has had for the intellectual knowledge of the history of Copenhagen and even for the understanding of modern cultural heritage in the streets of Copenhagen.