And what was their explanation for this?

Surely travelers and sailors must have noticed early in history that the length of the day depends on latitude, or at least that the length of a day is different in Northern Europe compared to the Middle East (for example). When was this first noticed? What did they make of this observation? When did people realize the less obvious fact that sunrise and sunset are offset from each other when travelling east/west? Did it predate our understanding that the Earth rotates? Also, when would the "man on the street" have realized that morning in Europe does not happen at the same time as morning in China (for example)?