St. Alphonsus Liguori relates a story about St. Dominic and the Rosary which strains credulity to the breaking point. Ultimately this story can be traced back to Bl. Alanus de Rupe.
Biography of Bl. Alanus de Rupe, also known as Alan or Alain. His cultus has never officially been approved, but he is customarily given the honorific 'Blessed.'