Fortuny became famous for his pleated dresses, the "Delphos" and the related "Peplos". The exact method of pleating was a closely guarded secret involving heat, pressure and ceramic rods, which has never been replicated. On both types of dresses, glass Murano beads are strung on a silk cord along each side seam. The beads serve a functional purpose as well as being decorative, as they weigh down the lightweight silk of the garment to ensure a smooth fit enhancing the natural, uncorseted human form beneath. The construction of the Delphos became its own decoration. Although the "Delphos" eventually became formal wear, with Lauren Bacall wearing a vintage red Delphos to the 1978 Oscars, it was originally intended as informal clothing or a tea gown for wearing solely in the privacy of the home.