Who decided the time of day and in what year?

The division of the day into hours can be traced back to ancient civilizations, notably the Egyptians, who created a 12-hour system for daytime and nighttime around 1500 BCE. However, the standardized 24-hour day we use today was popularized by the ancient Greeks and later adopted by the Romans. The introduction of mechanical clocks in the 14th century further solidified this timekeeping system in Europe.