The Egyptians loved their sundials.
The Chinese pushed water clocks to a higher art form.
In the early Middle Ages, time was first marked down the length of a candle in hourly increments. Next came large hour glasses, which were only good for an hour or maybe two or not at all if the "watchman" did not flip it over on time.
Then, Brother Gerbert, who later became Pope Sylvester II, invented a simple mechanism in 966 that rang bells at regular intervals throughout the day to call his brethren to prayer. It was the beginning of mechanical clocks as we know them today.
Eventually cathedral towers were providing the rest of the faithful with their first glimpse of a right proper mechanical clock. Keeping perfect time was not a strong suite of these early clocks. but it was a good start.
The earliest of these clocks is credited to Jacopo de Dondi, who designed an astronomical clock for the cathedral tower in Padua in 1344. Curiously, almost every zodiac sign surrounds the clock face except for the balanced scales of Libra. (As the story goes, it was deliberately left out of the lineup by guild workers who felt they weren't treated fairly in salary negotiations.)
Strasbourg Cathedral's mechanicall clock appeared in 1354, and was followed by the third, and most elaborate mechanical clock, built in Prague's Town Hall in 1410. (see earlier blogpost on this clock)
Having been created during the midieval times, the Prague clock depicted earth at the center of the universe - with the sun, moon, and stars revolving around it. Blue and red halves separated day and night. With embellishments added over the centuries, today the clock remains a veritable fun house of timekeeping.
It remains the city's most popular (and free) attraction, still packing them in as a mechanical rooster loudly crows, signaling the parade of the 12 Apostles, who enter from two open windows. The hourly show winds down with a 'hour glass of life' running on empty.
A skeleton, rattling its ancient bones, finally ends the observance that, an hour later, begins all over again as it has done for centuries.