Not all of the bands that have been a part of the history and development of progressive rock are necessarily progressive rock bands themselves. This is why a genre called Prog Related is included, so that all the bands that complete the history of progressive rock are included, whether or not they were considered full-fledged progressive rock bands themselves. There are many criteria that are considered when deciding which bands are prog related. Very few bands will meet all of this criteria, but this list will give an idea as to some of the things that help evaluate whether an artists is prog related or not:
1. Influence on prog rock
The groundbreaking work of artists like Led Zeppelin and David Bowie affected many genres of rock, including at times progressive rock. Although both of these artists created rock music in a dizzying array of genres, both contributed to the ongoing history of progressive rock several times within the span of their careers.
David Bowie-The Man Who Sold the World (The Man Who Sold the World, 1970 UK)
Asia-Heat of the Moment (Asia, 1982 UK)