Roman economy

Currency denominations

The early Empire was monetized to a near-universal extent, in the sense of using money as a way to express prices and debts. The sestertius (plural sestertii, English "sesterces", symbolized as HS) was the basic unit of reckoning value into the 4th century, though the silver denarius, worth four sesterces, was used also for accounting beginning in the Severan dynasty. The smallest coin commonly circulated was the bronze as (plural asses), one-fourth sestertius.Bullion and ingots seem not to have counted as pecunia, "money," and were used only on the frontiers for transacting business or buying property. Romans in the 1st and 2nd centuries counted coins, rather than weighing them—an indication that the coin was valued on its face, not for its metal content. This tendency toward fiat money led eventually to the debasement of Roman coinage, with consequences in the later Empire. The standardization of money throughout the Empire promoted trade and market integration. The high amount of metal coinage in circulation increased the money supply for trading or saving.

Rome had no central bank, and regulation of the banking system was minimal. Banks of classical antiquity typically kept less in reserves than the full total of customers' deposits. A typical bank had fairly limited capital, and often only one principal, though a bank might have as many as six to fifteen principals. Seneca assumes that anyone involved in commerce needs access to credit.

A professional deposit banker (argentarius, coactor argentarius, or later nummularius) received and held deposits for a fixed or indefinite term, and lent money to third parties. The senatorial elite were involved heavily in private lending, both as creditors and borrowers, making loans from their personal fortunes on the basis of social connections. The holder of a debt could use it as a means of payment by transferring it to another party, without cash changing hands. Although it has sometimes been thought that ancient Rome lacked "paper" or documentary transactions, the system of banks throughout the Empire also permitted the exchange of very large sums without the physical transfer of coins, in part because of the risks of moving large amounts of cash, particularly by sea. Only one serious credit shortage is known to have occurred in the early Empire, a credit crisis in 33 AD that put a number of senators at risk; the central government rescued the market through a small loan of 100 million HS made by the emperor Tiberius to the banks (mensae). Generally, available capital exceeded the amount needed by borrowers. The central government itself did not borrow money, and without public debt had to fund deficits from cash reserves.

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