Timeline of time measurement technology
- 270 BC – Ctesibius builds a popular water clock
- 46 BC – Julius Caesar and Sosigenes develop a solar calendar with leap years
- 1502 – Peter Henlein builds the first pocketwatch
- 1582 – Pope Gregory XIII, Aloysius Lilius, and Christopher Clavius introduce a Gregorian calendar with an improved leap year system
- 1656 – Christian Huygens builds the first accurate pendulum clock
- 1676 – Motion works and minute hand introduced by Daniel Quare
- 1680 – Second hand introduced
- 1737 – John Harrison presents the first stable nautical chronometer, thereby allowing for precise longitude determination while at sea
- 1928 – Joseph Horton and Warren Morrison build the first quartz crystal oscillator clock
- 1946 – Felix Bloch and Edward Purcell develop nuclear magnetic resonance
- 1949 – Harold Lyons develops an atomic clock based on the quantum mechanical vibrations of the ammonia molecule
