Why do we write price on the y-axis and quantity on the x-axis in a demand curve?

We write price on the y-axis and quantity on the x-axis in a demand curve -

While drawing graphs, generally, the dependent variable is placed on y-axis and independent variable is placed on x-axis on two dimensional graph.

But, in economics, the norm is opposite. If we draw demand (or supply) curve, we do not place dependent variable (that is quantity demanded or supplied) on y-axis and independent variable (that is price) on x-axis. Rather, on a demand (or supply) curve, price is placed on y-axis and quantity is placed on x-axis.

It is believed that the norm was created by Alfred Marshall, when he introduced the demand and supply curves. He, first, drew the demand and supply curves in his book " "Principles of Economics". Back then, while writing the book, he used to note down how much quantities were brought in, for different items, at given price (from local markets of London). He thought of quantity as independent variable, with prices adjusting to clear market. Thus, he drew the demand and supply curves, with price on y-axis.

Since then all other authors followed the convention and it becomes a practice to write down price on y-axis and quantity on the x-axis in a demand curve.