Well, what do you mean by on time?

Before mechanical timepieces became commonplace, the concept of meeting at a precise time did not really exist. It would be difficult for the average farmer in, say, 1600s Pennsylvania to schedule a meeting at 9:15am, because he wouldn't know when 9:15 was. What he did know was that he usually needed to be as productive as possible during the daylight hours, and that his livestock started moving around at or just before dawn. So, he went to bed when it got dark and awoke when it got light. Meetings could be planned by rough time of day - morning, noon, evening, etc.

I once worked in a historic house museum that had the (sadly unpublished) diary of the place's gardener. One of his entries noted that he had bought a watch. Before that date, every reference to time was vague, following the parts of the day. After that, he took great delight in being as specific as possible.

In some places in the early middle ages, time was told by church bells. Granted, it wasn't "on the dot" but in many places in Europe, specifically France and England, towns and villages would have at least one church. Some had several. There was a place in France (can't remember the name) that was nicknamed "the town of bells" or something to that effect because all of their churches would ring at the same time.

And with the use of a sundial or candle clock or some other method, priests and/or monks would keep track of the canonical hours and ring the bells accordingly. The town, whether they were actively religious or not, would often tailor their day around the bells.

For example, the first bell of the day would ring about dawn, signalling Matins. The markets may open and medieval housewives may ready themselves for shopping for the day.

Source: A book I own.

'On time' only became a real issue during the early modern period, and even then for the 'elites' living in cities and towns in Western Europe. 'On time' for the balance of people only came into play after the industrial revolution.

The below article refers to a number of studies by historians in the U.S. and Europe with respect to the concept of the 'second sleep.' My summary of this would be that, from prehistoric times up to the early modern period, humans slept from about 730 pm (sundown) until about 1100 pm. They would awaken for a few hours, visit with friends, pray, smoke, fornicate etc, and then go back to sleep again until sunrise or so.

Then, in the early modern period, the advent of cheap(er) candles as a source of lighting allowed the wealthier citizens in towns and cities to stay up late, drinking coffee in the newly fashionable coffee shops of Europe. This lead to a later bedtime and the roots of today's 'solid 8 hours.' Eventually, the widespread adoption of gas lamps and later electric lighting during the modern era, spread the concept of a solid 8 hours sleep across the strata of society.

Before this change to the way humans sleep, humans were less concerned with time in the sense we consider it today. An agrarian based society functioned according to the availability of sunlight, so people were geared to meet at 'dawn' rather than 0600 as we would be today.

As an aside, this thesis also suggests that many of the common problems humans have today regarding sleep disorders, insomnia, etc, are rooted in the (relatively) recent change to a solid 8 hours sleep!

http://m.bbc.co.uk/news/magazine-16964783

(NB I hope the source meets the requirements of the sub, it also contains references to the articles cited)

Thank you for all the comments! This is something that I have often thought about!

So is it safe to say, that in,say, medieval times, if you worked for an employer, " Being late" wasn't really a problem? Like no nobody would get fired for oversleeping?

What about the noble people? How would they schedule meetings with other towns or states? Based on what?