Sunday - Sun day, Monday - moon day, Tuesday - Tiw's day ( God of Battle) Wednesday - Woden's or Odin's day ( God of poetry and the dead), Thursday - Thor's day ( God of thunder) Friday - Friggs day (Goddess of married love) Saturday - Saturn's day (God of fertility and agriculture) I would imagine their origin is Roman or Greek as they are all connected with mythology, hope this helps. Judy