 "Flateyjarbók", from the end of the fourteenth century, is the most extreme example of expansion, interweaving Snorri's text with many "þættir" and other whole sagas, prominently "Orkneyinga saga", "Færeyinga saga", and "Fóstbrœðra saga".The text is also referenced in "Journey to the Center of the Earth" by Jules Verne; the work is the one Professor Liedenbrock finds Arne Saknussem's note in.By the mid-16th century, the Old Norse language was unintelligible to Norwegian, Swedish or Danish readers.