As the decade of the 1960s began, the United States had the “highest mass standard of living” in world history.1 The strong American postwar economy of the late 1940s and 1950s continued into the 1960s. In fact, from 1940 to 1960, the U.S. gross national product increased fivefold.2 There were several reasons for this economic growth.
So that there were certain things each kind of engineer had to do to get the job done, I'm guessing.
Autocratic authority was wielded by Islamic emperors.