The concept of timekeeping dates back to ancient civilizations. The earliest methods included sundials, which used the shadow of the sun, and water clocks, which measured time by the flow of water. Mechanical clocks were first developed in the 14th century in Europe, using weights, gears, and escapements to regulate time. The pendulum clock, invented by Christiaan Huygens in 1656, marked a significant advancement in accuracy. The development of portable timepieces, such as pocket watches in the 16th century and wristwatches in the 19th century, further revolutionized timekeeping. Modern clocks now utilize quartz crystals and atomic precision for unparalleled accuracy.