The mint law of the Indies (Recopilación, libro IV, títulos 23 and 24)
The law that put mints in Mexico City, Santa Fe de Bogotá and Potosí and then bound their output to a single standard: the same fineness, value, weight, dies and punches as the coin of Castile. It names every office in a mint, halves the Castilian seigniorage as a relief to the Indies, gates coining behind proof that the royal fifth was paid, and — in the next título — forbids anyone at all to trade in unassayed metal.
Why this wins its question: The Spanish silver dollar is written about constantly and the law that manufactured it almost never. This object transcribes that law from a digitised printing of the code, each provision with the monarch, place and date the compilers put in its margin: the 1535 order for mints at Mexico, Santa Fe and Potosí, the clause requiring identical fineness, weight, dies and punches to Castile — the legal act behind a coin that was accepted unweighed on three continents — the seigniorage cut from fifty maravedís to one real as a stated relief to the Indies, the named offices of a mint down to the Hornaceros, and the ban on unassayed metal that the crown extended to Spaniards and Indians alike. Beside them the code's own evidence against itself: the same rules reissued across four reigns, and provinces that had no coin at all.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The founding law is Recopilación libro IIII, título XXIII "DE LAS CASAS DE MONEDA, Y SUS OFICIALES", ley j, "Que en México, Santa Fe, y Villa de Potosí haya Casas de Moneda", with the marginal provenance "El Emperador D. Cárlos y la Reyna Gobernadora en Madrid á 11 de Mayo de 1535. Ordenanza 1 y 11". It ordains that in the cities of México, Santa Fé del nuevo Reyno de Granada and the Villa Imperial de Potosí there be mints "con los Ministros y Oficiales, que convenga para su labor y fábrica", and that in the city of Santo Domingo of the island Española vellón be struck when the crown gives special licence.
What could be struck was narrow and was fixed early. Ley iij, "El mismo Ordenanza 1. de 1565", commands that in the Indies silver coin be struck and not gold, nor vellón unless the King permits it; ley iiij, "El Emperador D. Cárlos en Monzon á 18 de Noviembre de 1537", allows the mints of the Indies to strike "reales de á ocho, y de á quatro, de á dos y de uno y medios reales como en estos Reynos" — the eight-real piece that circulated for three centuries is the first denomination the code names.
The rule that made the coin usable anywhere is one sentence. Ley ix, "Que la moneda de plata sea del mismo valor, peso y cuño, que la de estos Reynos de Castilla", with the margin "El Emperador D. Cárlos, y el Príncipe Gobernador en Valladolid á 10 de Mayo de 1544. D. Felipe II en Córdoba á 8 de Marzo de 1570. D. Felipe IIII en Madrid á 2 de Abril de 1651", reads: "Toda la plata que se ha de labrar ha de ser de la misma ley, y valor y peso, sin diferencia en los cuños, punzones y armas, que la de estos Reynos de Castilla. Y en Potosí, y Nuevo Reyno de Granada, se guarde lo ordenado en quanto al cuño en moneda de columnas." A coin minted in the Andes was by law the same object as a coin minted in Seville.
The crown taxed the coining, and the same law records that it taxed the Indies more lightly than Castile. Ley vij, "Que de cada marco de plata se cobre un real de señoreage" (Philip II at Madrid, 15 February 1567; Philip III at Ventosilla, 26 October 1613, at Madrid, 20 January 1615, and 1 April 1620), states that the seigniorage is due by right, that in Castile "percibimos á cinquenta maravedís por marco de plata", and that "por hacer bien y merced á nuestros súbditos, y naturales de las Indias, y aliviarlos quanto fuere posible" only one real per mark shall remain to the crown in the Indies for the right of seigniorage or coinage, the officials of the royal treasury keeping account of its collection.
Ley viij fixes the workers' cut and explains it by the cost of living in the Indies. Because by the ordinances of the mints of Castile sixty-seven reales are drawn from each mark of silver, of which so many are reserved for all the officials, "y por ser los gastos de las Indias excesivos, conviene darles mayor recompensa, para que mejor puedan acudir á su trabajo, y tengan congrua sustentacion", the officials of the mints of the Indies may take three reales from every mark coined there, distributed as in Castile — two reales for costs and charges and the third for the seigniorage.
Coining was gated behind the royal fifth. Ley vj, "Que en las Casas de moneda no se labre plata sin la marca del quinto", carried across four reigns (Charles and the Empress Governor, ordenanza 4 de 1535; Philip II, ordenanza 5 de 1565; Philip III at Madrid, 21 April 1600; Philip IIII at Zaragoza, 18 June 1646), orders that in no mint of the Indies silver be received to be coined "si no estuviere primero marcada con nuestra marca Real, por donde conste que está pagado el quinto". The tax was taken from the metal before it became money.
The code names the whole establishment of a mint, which is why it is worth reading rather than summarising. Ley xiiij (Philip II at the Bosque de Segovia, 21 August 1565; Philip III at San Lorenzo, 25 October 1620; Philip IIII at San Lorenzo, 25 October 1625) requires in every mint "un Tesorero, un Fundidor, un Ensayador, un Marcador, un Balanzario, un Blanqueador, un Tallador, un Escribano, y dos Porteros, y guardas, y algunos oficios menores, como son Afinadores, Acuñadores, Vaciadores, Hornaceros", plus others proposed by the treasurers and approved by the viceroys or presidents, and orders that those who serve them be persons fit for the exercise and the ablest available.
A large part of the título is anti-fraud machinery, and it reads as a catalogue of what was being done. Ley xv forbids any official of a mint to trade in fine silver, or silver unmarked or unquintado, on pain of privation of office, perpetual banishment from the province and forfeiture of goods; ley xxj (Philip II at Madrid, 3 August 1567) orders the escobilla — the sweepings of precious metal — kept under two keys, one held by the Fundidor and one by the Factor, and the smelting done where the royal treasury chest is; ley xxij (Charles at Monzón, 5 June 1528) forbids the Fundidor, Marcador or anyone who handles the smelting to hold the escobilla by lease or encomienda, and provides that gold or silver spilled or fallen in the forge may be sought and taken by its owners without impediment.
Jurisdiction over the mints was kept with the ordinary courts, not with the mints themselves. Ley xij (Charles and the Empress Governor, ordenanza 5 de 1535; Philip II, ordenanza 6 de 1565) lets the royal audiencias and the ordinary justices of the cities and towns where there are mints take cognisance of any crime of falsity of coin, even one committed by the moneyers inside the house; ley xiij has the viceroys of Lima and Mexico and the president of the audiencia of Santa Fe name the judges who take residencia of the alcaldes and officials of the mints in their districts every two years.
The moneyers' privileges were bounded in the same breath as they were granted. Ley xvij (Charles and the Empress Governor, ordenanzas 8 and 12 of 1535) rules that the exemption from pechos and monedas which moneyers enjoy under the laws of Castile "no se extienda á las alcabalas, quintos, almojarifazgos, y otros tributos, impuestos con repartimiento, ó hacienda de que les hiciéremos merced".
The next título states the policy behind the mints and names its victims. Libro IIII, título XXIV "DEL VALOR DEL ORO, PLATA, Y MONEDA, Y SU COMERCIO", ley j (Charles and the Kings of Bohemia Governors at Valladolid, 16 April and 7 July 1550; Philip II at Aranjuez, 4 March 1561), prohibits universally to all persons of whatever estate or condition to contract in gold or silver in powder, in tejuelos, or unmelted, unassayed and unquintado, on pain of losing it. The reason given is that "los Españoles, é Indios contratan con oro, y plata corriente, sin quintar, pesándolo con pesos falsos, y por mayor, y adulterando algunas veces el oro, ó plata, de que resultan muchos daños á nuestros vasallos, y Real hacienda"; and the law adds "que la misma prohibicion se guarde con los Indios".
The same título records that the system did not reach everywhere. Ley ij (El Pardo, 1 November 1591) recites that the want of coin has occasioned the use of gold or silver corriente in some provinces of the Indies, contrary to the prohibition, and orders viceroys, audiencias and governors to see that where trade cannot be carried on without it the metal be made into coin, and that the principal cities, where coin was abundant, send a quantity of reales every year with the fleet to the province that lacks it.
What this evidence is, and is not, belongs on the record. The Recopilación is the law as codified: it establishes what was ordered, by which monarch and on what date, and — through the repetition of the same prohibitions across four reigns — that the orders were being broken. It carries no mint output figures, no assay results and no measure of enforcement, and it does not by itself establish which American mint struck first. Nothing here should be read as a production history.