From BrWiki
A domain's treasury is measured in gold bars (GB). A gold bar abstractly represents things of worth owed to the regent, be they in cash or commodity, in service or in kind. The default gold bar is roughly equivalent to 2,000 gp in coin value if quickly disposed of, but this value may differ regionally. The things of worth represented by a GB varies by the nature through which the revenue is generated – generally through taxes on commodities, but also in part direct seizure of such (the lord’s share of corn, ground wheat, etc.), and extraction of certain feudal services (including military obligation or scutage). A GB of value often consists of a wide variety of things of value. The exact nature of these things is usually irrelevant, as GBs are only used to finance domain level actions and pay for domain actions.
