Understanding how money was counted and utilized during certain periods in history is often helpful in genealogical research. For instance, if you find in a will that the family had personal belongings that were valued at a certain amount, you could judge approximately the social rank or status of the family. For those of us who share an "English" background, the silver penny is the foundation.
A post titled: "The Silver Penny" outlines this topic:
A text titled: "The World We Have Lost, England Before the Industrial Age", by Peter Laslett, gives a number of tables which help define social class during the period prior to 1700. A very valuable reference.