Historically, the people of the Seven Kingdoms of Westeros used coins containing silver as money.

Before its government got involved in the countrys monetary system, the Seven Kingdoms had coins that were produced by private mints. Often, these mints were owned by prominent nobles. One of them was owned by Tywin Lannister, the head of House Lannister, an extremely wealthy house that dominated the western part of the Seven Kingdoms. The coins produced by this mint provided most of the currency in the westlands, and they were very commonly used elsewhere in the Seven Kingdoms.

Following traditional practice in the Seven Kingdoms, the Lannister mint used monetary units known as stars. Its most popular coin was a silver dragon whose denomination was seven stars. (Seven was an important number in Westeros: in addition to the seven kingdoms, the principal religion in Westeros featured a god with seven aspects.) These coins had a picture of a dragon engraved on one side.

The mint named and marked the coins in this way to honor House Targaryen, the house of the Lord of the Seven Kingdoms, who governed them from the Iron Throne in the city of Kings Landing. The symbol of House Targaryen was a dragon.

For many years, the Lannister mint bought silver and produced dragons (dragon coins) at a mint price of 9 stars per ounce of pure (fine) silver. The mint equivalent was 10 stars per ounce of silver. A dragon weighed 4/5 ounce, so these coins were not pure silver.

The staple food in the Seven Kingdoms was bread, as in all the other nations in the region. Bread was widely traded across national boundaries, as was silver.

In all these nations, bread could be purchased, using raw (uncoined) silver, at a rate of 25 loaves per (Troy) ounce. This price was determined by international market forces, and it was not influenced by the monetary actions of any individual nation in the Known World.

Initially, the price of bread in coins depended largely on the value of the coins silver contents. However, because of the superior convenience of coins in exchange, silver in coins was worth a bit more than uncoined (raw) silver. For example, a person could buy 21 loaves of bread with a dragon.

Q: What was the price of a loaf of bread, in stars? How much did 25 loaves of bread cost, in ounces of silver in monetary form (silver contained in coins)?

Q: How much less, as a percentage, did 25 loaves of bread cost in ounces of monetary silver, compared to their price in ounces of raw silver?

Q: How much purchasing power, in loaves of bread, would a person who brought an ounce of raw silver to the mint have gained or lost by doing so?

Q: At some point, the Lannister mint secretly started debasing the coins it produced, increasing its actual mint equivalent to 12 stars per ounce. It left the mint price at 9 stars per ounce, and it continued to claim, falsely, that its mint equivalent was 10 stars per ounce. It also reduced the total weight of the debased dragons very slightly, to 7/9 ounce. What was the debasement rate, in percent? What was the fineness of the debased dragons, in percent? How many stars in coins did the mint now produce from 7 Troy pounds of silver? How many dragons?