Supposedly introduced by Howard & Smith Nursery, California, USA in 1930's, but no documentary evidence to support this nursery-man assertion. It was claimed to be a member of the Grand Opera Series, originally developed by Howard and Smith. Wayside Gardens reputedly later purchased the series and added their own 'Rosenkavalier'. All cultivars in the series have large flowers in pastel shades, green foliage and are quite tall.
However, the series also contains some Italian Group cultivars and they don't happen easily or accidentally, and are out of sync with the other Crozy Group cultivars in this series. They also bear a remarkable resemblance to cultivars that were developed many years before this series was supposedly developed. Suffice to say that I suspect that this was a marketing exercise by Wayside Gardens to repackage older varieties.