I've actually written about this a bit before -- excuse the brevity but I'm on mobile about to board a plane. It was understood in classical antiquity that time was different in different places, and in fact measuring the differences in time in different places was an early proposal for measuring the earth's circumference. In the period I study, ships would set their time by local noon daily, but "ship lag" wouldn't amount to much before steamships. I wrote more about this here: https://m.reddit.com/r/AskHistorians/comments/3uufv2/when_did_people_understood_the_concept_of_time/