Asiento (Slave Trade Charter Contract)

Timeline

1. 1551–1579Casa de Contratación, Seville · AndalusiaBefore the general contract appeared, the crown sold licenses to import slaves piecemeal to merchants, especially Portuguese ones, since Portugal controlled the West African trading posts. Licenses were priced per head or per voyage, yielding limited fiscal returns and unable to uniformly curb smuggling beyond quotas. The term asiento already existed at this stage, but exclusive general contracting had not yet formed.
2. 1580–1589Lisbon–Seville · Iberian PeninsulaAfter Philip II also ruled Portugal, the slave sources of Angola and Upper Guinea and the Spanish American market belonged to one monarch, making it easier for Portuguese merchants to obtain supply contracts for Spanish America. After the Angolan colonial outpost expanded in 1575, the Angola route gradually overtook Upper Guinea, providing sources for the later general contract.
3. 1582–1594Madrid · MadridAfter the indigenous labor force in the Americas was exhausted, the court debated for years whether to continue selling licenses piecemeal or to award the quota as a general contract to a single contractor. Casa de Contratación officials worried about the outflow of precious metals and foreigners monopolizing "necessary goods," while contractors promised higher annual payments. The debate pushed the asiento from case-by-case licensing toward a fiscal monopoly contract.
4. 1595–1601Madrid–Lisbon · Iberian PeninsulaPortuguese merchant Pedro Gómez Reynal obtained a general contract of about nine years: transporting up to about 4,250 slaves per year to Spanish America and paying about 100,000 ducats annually to the treasury, while reselling licenses himself at about thirty ducats each. The contract established the basic terms of subsequent Portuguese asientos and was terminated early in 1601 due to excessive resale prices and fraud.