Everything has its beginning. And if you believe that time starts from somewhere, also consider the beginning of time measurements.
Early people have devised a system to tell the exact date. But a device that exactly tells the precise time comes much later. Water clocks, sundials, and candle clocks are the earliest instruments that somehow manage to tell time but accuracy is far from achievable.
In the 13th century, weight-driven clocks were developed. It used gears while hour hand was already used while the minute hand was an indication of luxury and wealth. The weight-driven clocks were publicly displayed on church towers, city halls, and monasteries.
In the 16th century, clocks were produced using spring instead of weight. The portable clocks or the pocket watches were the first timepieces that the public can own. During this time, the only persons who can own them were the rich and owning one signified the status, authority, and wealth of the person. Often, portable watches were placed on the wall of the house. The term portable though did not mean it could be carried on your pocket. The term changed its meaning some years later.
The first transportable watches or pocket watches was used also in the 16th century. This time, clocks no longer had to stay at one place. Pocket watches can already be worn around the neck or carried on a pocket. The same era also brought revolution to the development of pocket watches. Mechanisms were introduced to bring time-telling precision. Some packet watches even had an alarm.
The entry of the 17th century made pocket watched even more desirable. The box-like image was removed and was replaced by more rounded and slimmer cases. Clockmakers also became instant artists as they infuse designs and craftsmanship to every pocket watch the made.
When Christian Huygens discovered the law of pendulum, which for your information was different from Galileos, clock had yet again moved one step further. The law proved to be very helpful in the development of pocket watches.
In the 18th century, pocket watches continued to evolve. This time, jewels were used as bearings. Diamonds became part of some pocket watches that boosted the price of a single pocket watch to the ceiling. Oil was also became part of pocket watches during this period. This was to lubricate and smoothen the movement of the watchs hands. In the second half of the 18th century, pocket watches were produced with three hands. Contrary to the inclusion of the minute hand during the 16th century, second hand made sense since accuracy in telling time was far better.
In the 19th century came the glory days of the packet watches. This era brought the several watchmakers into the picture. Names such as LeCoultre & Cie, Ulysse Nardin, Minerva, Heuer, IWC, and many others were established in this period. The quality of pocket watches became better than ever.
By the turn of the 20th century, certificates were issued to those watchmakers that created precise watches. Unlike the previous years, issuance of certificate became more of a requirement than luxury.
And as the years gone by, the popularity of pocket watches diminished as wristwatches became more popular.
Although pocket watches are not so much used today, it has served as one of the important instruments for several centuries.