mobility in the Roman Empire. Social advancement was thus not dependent solely on birth, patronage, good luck, or even extraordinary ability. Although aristocratic values permeated traditional elite society, a strong tendency towards plutocracy is indicated by the wealth requirements for census rank. Prestige could be obtained through investing one's wealth in ways that advertised it appropriately: grand country estates or townhouses, durable luxury items such as jewels and silverware, public entertainments, funerary monuments for family members or coworkers, and religious dedications such as altars. Guilds (collegia) and corporations (corpora) provided support for individuals to succeed through networking, sharing sound business practices, and a willingness to work. Currency and banking 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 towards 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 Roman 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