This is a vintage Simplicity pattern. The pattern is for Misses’ fashion basic princess dress with two necklines.
Size 10 (Bust 32 ½)
It is described on the pattern envelope as “The collarless dress with princess seaming has back zipper and optional purchased belt. V.1 has high round neckline and long set-in sleeves. V.2 & 3 with lowered round neckline have top-stitching trim. V.2 has short set-in sleeves. V. 3 is sleeveless.”