From shells and spice to shekels and mites

How about a little frankincense for your birthday? It might not be your first choice for a present today, but at the time Jesus was born, it was a valuable gift. Suppose you lived in a country that had no banks, no checking accounts, no credit cards, and no paper money. Coins were rare. What would you do if you wanted to buy some candy? You'd have to go to the person who made candy and offer to trade something or do some work in exchange for the candy.

That's how people got the things they needed before money came into use. Thousands of years ago, people usually lived in small villages. They raised most of their own food, built their own simple homes and furniture, and made their own clothes. Or they might trade with a neighbor, giving him grain in exchange for animal hides or sheep's wool.

Then villages got bigger and people began to specialize. One person became a carpenter, another raised cattle. Trading became more common. But what would a weaver do if he needed bread, and the baker didn't need cloth? He might try to find out what the baker did need, perhaps some firewood, and trade cloth to someone else for firewood, then trade that to the baker. It could get pretty complicated.

So people began to assign values to items that were easy to trade, such as shells, beads, and metals like gold, silver, and copper. Because these metals had to be mined and refined, they were very valuable. At first these metals were traded in lumps called ingots. The ingots were stamped with information about their weight and value. Merchants would still have to weigh the ingots each time, though. Some metal might have been chipped or shaved off. Sometimes a merchant took a little nick out of the ingot to see if it was solid gold or contained some other metal inside.

Historians think the first coins may have been created, or minted, in about 700 BC in Lydia, a region in modern Turkey. These coins were round lumps of precious metals with their weight stamped on them.

A good coin would have a large seal on each side covering the entire area of the coin. That way, people could tell if any of the metal had been chipped or shaved off. (The ridges - called "reeding" - around the edges of modern coins were originally added so that you could tell if any metal had been nicked off.) The seal might be a picture of an animal, a politician, a god, or some other object. Traders brought coins to Greece and Iran, and their popularity grew.

By the 5th century BC, coins were being used throughout much of the Middle East and Mediterranean region. Rulers had coins minted to mark important events or with their pictures on them. Ancient Jewish coins were produced during only a relatively short period from 134 BC to AD 135.

Since coins in biblical times were hand-made, each might have a different weight and value. Merchants had to weigh the coins each time a trade was made. They used a set of balancing scales to do this. To weigh the coin, it would be put on one side of the scale, and counterweights of a known weight would be put on the other side until the scales balanced. Then the merchant knew that the coins weighed the same as the counterweights on the other side.

Scales like those used to weigh coins in biblical times have been traced back to 3000 BC in Egypt. They may have evolved from the shoulder yokes worn by people to carry heavy loads. The wooden yoke went across the carrier's shoulders and burdens were hung from the ends, divided equally so the load would balance. Balance scales are still used by scientists today to weigh tiny amounts of chemicals and other items.

To find out if a coin was made of pure gold without melting it down or damaging it, merchants used another invention from Lydia: a touchstone. Touchstone is a fine-grained velvety black rock, a kind of quartz. When a gold coin is rubbed on a touchstone, it leaves a stripe of a particular color. The color of the stripe is compared to the mark made by gold of a known purity. The test is quite accurate.

By the time Jesus was born, people in his region were familiar with coins. It's not likely that they used them for all their purchases, though. Bartering was still very common, and trades involved not only coins, but also other items of worth such as frankincense and myrrh.

In the story of the three wise men visiting Jesus at his birth, three scholars in a country far to the east of Jerusalem notice an unusual occurrence in the night sky. They know from their studies that this is the sign of an important event. They are Magi, who have studied how to read the signs of the sky and interpret them. Their job is to make predictions based on these observations, and they are well paid by members of the royal court. The Magi's pay might have been in the form of gold and silver coins, but also in valuable spices and other items. Spices were highly valued in Bible times. Frankincense and myrrh were burned as incense during worship and used in making perfumes. They were also used as medicine or in burial preparations. And items such as these were also a form of currency, because they were valuable and easy to carry around.

So when the Magi find the newborn king, they give him the same royal gifts that they have received from princes and kings - gold, frankincense, and myrrh. They also warned the baby's parents that Herod, the pro-Roman Jewish governor of Galilee, feared the baby could threaten his throne. Herod, they said, might try to harm the child. So Mary and Joseph took their infant to Egypt, perhaps using the gifts of the Magi to pay their way and support them while they were in hiding.

As more metals were mined and refined, coins became more common. Eventually, most purchasing in developed countries was done with coins and then paper money. Now we also have checks, credit cards, and debit cards. Large sums of money change hands without any materials at all, but simply as numbers sent and received electronically. In today's society, wise uncles and aunts may give children gifts in the latest style: gift certificates from Internet shopping sites.

• Nov. 23 to 30 is National Bible Week in the United States.

A teeter-totter (or do you say "seesaw"?) is a modern example of the kind of scales used to weigh coins in biblical times. You can make your own simple balance scale using a pencil and a ruler. Put the pencil on a table. Now balance a ruler on the pencil by placing the ruler flat across the pencil, perpendicular to it.

Once you get the center of the ruler exactly on the pencil, the ruler will balance. Both ends will be in the air. Take two paper clips and carefully place one at each end of the ruler. The ruler should still balance.

Now try putting a large paper clip on one side and a small one on the other. Your scale will overbalance. Can you add a second paper clip to make your scale balance again? Or try sliding the pencil closer to the heavier clip. Can you make it balance that way? By moving the pencil, you're changing the scale's center of gravity.

This "center of gravity" principle was used by Romans 2,000 years ago to weigh heavy objects. Instead of using an equal-armed scale, one with a short arm and a long arm was used. A heavy object was hung from the short arm of the scale. A lighter object was moved up or down the long arm until the two arms balanced. Markings on the long arm showed the weight of the heavy object. Today this is known as a steelyard scale.

Coins as money didn't start to be common until about 500 BC, and a shekel was a unit of weight before it was a coin. So some Old Testament references to "10 shekels of silver" mean silver that weighs 10 shekels (about 4 ounces), not 10 silver coins.

To add to the confusion, when shekels became coins, there were "light" shekels and "heavy" shekels. "Light" ones had only half the value of "heavy" ones. So how much would a shekel be worth today? It depends. Modern scholars put its value at between 32 and 64 cents.

Judas Iscariot's infamous "30 pieces of silver," the bribe he was paid to betray Jesus, was a unit of 30 shekels called an "argurion." An argurion was the fee required from someone who accidentally killed a servant.

Three thousand shekels made up a unit known as a talent. A silver talent was worth $960 to $1,920 and weighed between 38 and 76 pounds (depending on whether the shekels were "heavy" or "light"). A talent of gold was valued at $14,400 to $28,800. (See the parable of the servants and the talents in Matt. 25.)

And the widow's two mites, which she cast into the treasury (Mark 12:42)? Worth about 1/8th cent apiece.