The earliest evidence of weighing scales, specifically balance scales, dates back to ancient civilizations like the Egyptians and Romans, around 3100 BC, used for trade and commerce. 

Here's a more detailed look at the history of scales:

Ancient Origins:

The oldest known examples of weighing scales are balance scales, consisting of a beam with a pivot point and two pans hanging from each end. 

The ancient Egyptians used balance scales for trade and commerce, with evidence found in the tomb of an Egyptian pharaoh who died in 2300 BC. 

The Indus Valley civilization also developed standard weights and measures around 2000 B.C. 

The balance scale was likely used to determine relative mass long before absolute mass, with the oldest attested evidence for the existence of weighing scales dating to the Fourth Dynasty of Egypt. 

Evolution of Scales:

15th Century: Leonardo Da Vinci created a self-indicting scale. 

1770: Richard Salter invented the spring scale. 

20th Century: Electronic scales were introduced. 

Significance:

The balance scale was a simple yet efficient tool for determining the value of goods, with merchants placing goods on one pan and currency metals on the other. 

The development of more accurate weighing scales, like beam scales and steelyards, allowed for greater precision in trade and commerce. 

The invention of the spring scale by Richard Salter in around 1770, the weighing balance no longer relied on counter weights.