"järnnätter" (Swedish for "iron nights") especially in early June, which are susceptible to frost. The term may have arisen out of a mistranslation of German sources, where the term "Eismänner" (German for "ice men") was read as "Eisenmänner" (German for "iron men") and their nights then termed "iron nights," which then became shifted from May to June. See also Seven Sleepers Day Weather saints References Further reading Brewer, E. Cobham. "Ice Saints or Frost Saints", Dictionary of Phrase and Fable, 1898 Christian saints in unknown century Groups of Roman Catholic saints Weather lore Year of birth unknown