Leonardo da Vinci (1452–1519) investigated the phenomenon of friction and the conclusions he reached were eventually discovered and formalized by the French physicist and inventor Guillaume Amontons (1663–1705) as two laws:

1. The force of friction is directly proportional to the applied load;

2. The force of friction is independent of the apparent area of contact (i.e. if two bodies of equal mass and made from similar material are both in contact with the same third body, the same amount of force will be required to move them across the surface of the third body regardless of differences in the area of contact).