Early Accounting * Accountancy has its roots in the earliest history of civilization. With the rise of agriculture and trade, people needed a way to keep track of their goods and of transactions. Around 7500 B.C., Mesopotamians began using clay tokens to represent goods, such as animals, tools, food items or units of grain. This helped owners keep track of their property. Instead of counting heads of cattle or bushels of grain every time one was consumed or traded, people could simply add or subtract tokens. Different shapes were used for different goods. Around 4000 B.C., the Sumerians began placing these tokens in sealed clay envelopes. Each token would be stamped into the clay of the outside of the envelope, so the owner would know how many tokens were inside, but the tokens themselves would be kept safe from tampering or loss. This practice of pressing the tokens into the clay may have been the earliest genesis of writing. A few hundred years later, more complex tokens began to be used. These tokens had special markings to denote different units or types of goods. Starting around 3000 B.C., the Chinese developed the abacus, a tool for counting and calculating. * Basic principle

Revenue principle
The revenue principle, also known as the realization principle, states that revenue is earned when the sale is made, which is typically when goods or services are provided. A key component of the revenue principle, when it comes to the sale of goods, is that revenue is earned when legal ownership of the goods passes from seller to buyer. Note that revenue isn't earned when you collect cash for something.
Expense principle
The expense principle states that an expense occurs when the business uses goods or receives services. In other words, the expense principle is the flip side of the revenue principle. As is the case with the revenue principle, if you