In the lands of Ironbound, wealth, trade, and physical mass are anchored by a single, ubiquitous baseline: the Silver Penny (sp).

While empires rise and fall and local lords mint their own regional coinages, true commerce relies on the universal standard defined, blessed, and preserved by the Temple of the Merchant Goddess.

The silver penny is not enforced at the point of a sword or through heavy-handed royal taxation. Instead, its supreme authority is maintained entirely through ubiquity.

* The Reference Shrines: The Temple of the Merchant Goddess is the most widespread religious institution on the continent. Even in small hamlets or lawless frontier towns, a shrine or traveling clerk of the Goddess can almost always be found. * The True Weight: Every official shrine houses a “Veritas Coin”—a master-weight and purity gauge sealed in brass or carved stone. * Universal Convertibility: Because merchants everywhere trust the Temple's baseline, a silver penny minted in a distant realm is readily accepted if it matches the divine weight, bypassing the need for unpredictable exchange rates.

In the rules, the silver penny serves a dual purpose: 1. As Currency ($sp$): The standard medium of exchange for gear, services, and bribes. 2. As a Unit of Mass: Used for weighing small, precious, or standardized items (such as spell components, gems, or fine metals) where exactness matters.