Did the ancients have knowledge of time zones, due to communication you wouldn't think they know whether one place has a different time than another, or is it a modern discovery?
"Time zones" are a creation of the modern era, designed when travel became fast enough that railroads had to agree on standardized times. If you don't do that, you can get a situation where two trains are on the same tracks at the same time. if that happens, you are going to have a bad day.
But the idea that time was different at different places on the earth at the same time (if that makes sense) was known in the ancient world. I wrote about this before:
To quote from that a bit:
Hipparchus of Nicaea (c. ~190-120 BCE) seems to have been the first person to propose using a grid system to find the position of cities (and other places) on a globe, which implies an understanding of longitude. He built on earlier work by Eratosthenes of Cyrene (c. 276-194 BCE), who had mapped the known Earth, including finding its circumference. Hipparchus' method of finding the longitude of places was to use the differences in timing of lunar eclipses at different points on the globe to calculate the difference between local time of those points; the drawback is that there was no accurate-enough method of timekeeping to lead to useful calculations. Edit to clarify: The difference in local time between observed beginning and end of the eclipses would serve, essentially, as a way to understand the longitude between places.
The knowledge that local time would be different at different points on the globe is what led eventually to what's called "the discovery of the longitude" in around 1760 or so, when two methods of reliably finding longitude using time were discovered and implemented.