"killing seven flies at one blow, like the Little Tailor in the fairy-tale, as it were"

    The Valiant Little Tailor is one of the European folk tales collected and popularised by German scholars Jacob and Wilhelm Grimm in the early 19th century.  A tailor's boasts about killing seven flies 'at one blow' are misinterpreted by a giant as referring to seven men, which in turn leads him on a series of outlandish adventures in which his ability to exaggerate the valour of his deeds gains him increasingly great rewards.

Online edition of the Grimms' Fairy Tales, as translated by Edgar Taylor and Marian Edwardes, (1814)