Complex sentence: Progressive jazz is a form of big band that is more complex or experimental that originated in the 1940s with arrangers who drew from modernist composers such as Igor Stravinsky and Paul Hindemith.
Split into simpler sentences: Progressive jazz is a form of big band that is more complex or experimental. It originated in the 1940s with arrangers who drew from modernist composers such as Igor Stravinsky and Paul Hindemith.