I've read quite a bit about the use and reconciliation of various yearly calendars (e.g. lunar, Jewish, Muslim, Chinese, Julian, Gregorian, etc.) but I feel like I've never heard anything about how and when the current default timekeeping system came to be the standard. It is so pervasive I don't even know what its name is, or if it even has a name!

The only semi-alternative that I've heard of could be described as a "natural/primitive" timekeeping system of using sunrise, sunset and high noon as reference points. But that can't be the only alternative. If I know anything about history, it's that something as precise and detailed as the hour/minute/second system does not come to dominate every developed culture on the planet without trial, error, debate, conflict and revision. So tell me, AskHistorians, what's the untold story?