Butterick 6520 is a seventies pattern for a loose-fitting dress with a yoke and dropped shoulders. There is no copyright date on the pattern but my guess is mid-1970s. My fabric is a royal blue floral from Hawaiian Fabric.
Other than adding 5cm to the length, I made the pattern without alteration. When wearing the finished garment, I found that it tugged at the sides when I raised my arms. I did not find it comfortable to wear and did not keep the garment. There are better dress patterns.
The number Butterick 6520 applies to larger sizes of this pattern. Smaller sizes are sold as Butterick 6519.