One of the first methods to calculate the time was the Meridian that was using the Sunrise and Sunset of the day. Even the Moon could be used as a watch because there was precision with the regularity of intervals of time. The Moon and the Sun however, could not measure exact units of time. Navigators required an instrument that would allow them to be able to judge times and distances of travelling from one point to another. The introduction of John Harrison's marine chronometer triggered the invention of one of the most popular and well used inventions of all time: the watch. Up until this creation time keeping was famously unreliable. The first pocket watch to be used in every day life was created by Peter Henlein in 1524. This device was the beginnings of something quite remarkable and though it only had an hour hand (minute hands were not possible at this point as a result of their tendency to be inaccurate) it opened up a world of opportunity. To be able to tell the time changed how we live our lives today.
In history there were many methods used to measure the unit of time; some were done with candles and some with water watches which were more popular.
All those devices presented disadvantages however; in the first place they needed constant surveillance because, for example, when the candles were all burnt out it needed to be changed quickly so as not to lose any time. But probably the biggest inconvenience was that with those methods they were not a universal and unique champion of time.
