This is sewing pattern Simplicity 6657 from 1984. It is trademarked by the Cinderella Clothing Industries, Inc. The pattern features 3 different styles of dresses that could be made. There are 12 pieces to this pattern.
Girl's size 8
The paper envelope has the usual wear around the edges consistent with something vintage. The paper instructions have some slight yellowing around the edges but are in overall good, unused condition. The tissue paper pattern is uncut/unused and in very good condition.