Differences in standards may be necessary for any number of reasons: cultural, political, legal or financial. The following example helps to illustrate how the relationship between metrology (i.e., the science of weights and measures) and standards traces back through time . . .

In the earliest days of recorded measurement, the “Royal Egyptian Cubit” was decreed to be equal to the length of the forearm from the bent elbow to the tip of the extended middle finger . . . plus the width of the palm of the hand . . . of the Pharaoh or King ruling at that time.

Though the method used to define a unit of measure was fixed, the measurement itself could change over time depending upon the height of the current Pharaoh or King and the lengths of his arm.

Jumping forward several centuries to 1120 AD, King Henry the First of England made his contribution to the standardization of measurement by instituting the Ell, which was equivalent to the length of his arm.