The mechanical clock comprises an oscillating mechanism that marks the passing of time, and an escapement that counts its beats. By comparison with astronomical systems for measuring time, the mechanical clock is less accurate, but can be consulted at any time of day or night, even in adverse weather conditions.

The mechanical clock, which derived from water clock, was born in medieval Europe. The first mechanical clocks were large devices made of iron. By the fourteenth century, they were in widespread use across Europe. The same period also saw the construction of complex mechanisms primarily intended not to tell the time, but to reproduce the motions of the heavenly bodies and the relations between them. Two examples are Giovanni Dondi's famous Astrario and Lorenzo della Volpaia's Planetary Clock.

The first tower clocks were actuated by cogwheels pulled by a weight, whose force was regulated by a device called an escapement. However, beginning in the sixteenth century, clock-makers were able to replace the weight with springs and spindles or "conoids" that ensured the same regular movement. This innovation made it possible to produce ever smaller clocks. The clock thus found a place in the halls of palaces, on walls, on mantelpieces, and even in people's pockets.