At what time people understood or realized that there are changes in times between countries and continental, and when it's a day in one place it's a night in another place? Allegedly, It makes sense that in the past people thought it's the same time everywhere.
Different people disovered or realized that time changes with longitude at different times. For most of history most people never traveled more than a few dozen miles from their birth places. The rare people who travelled hundreds or thousands of miles travelled so slowly they wouldn't notice time differences. So the idea of time zoness only became well known in recent times.
When people discovered the earth was spehrical - knowledge that took centuries or millennia to become known to the majority of people - they realized that there were different times of day at different longitudes.
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