Theroyal fifth (Spanish:quinto del rey), (Portuguese:quinto real) is a historical royaltax which reserves to themonarch 20% of all precious metals and other commodities (includingslaves) acquired by his subjects aswar loot, found astreasure or extracted bymining. The 'royal fifth' was first instituted inmedieval Muslim states from interpretations of Qur'an, though the extent to which it applied was debated between schools of Islam. During theAge of Exploration, ChristianIberian kingdoms and their overseascolonial empires also instituted the tax, though to encourage exploration, some monarchs allowed colonists to keep some or all of the fifth.
The 20%tax rate onwar booty stems from the practice ofkhums (Arabic:خُمْس,lit. 'fifth') inIslamic states.[1] It was institutionalized from the start of theIslamic conquest, with the rate set down in Qur'an 8:41:
Know that whatever spoils you take, one-fifth is for Allah and the Messenger, his close relatives, orphans, the poor, and ˹needy˺ travellers, if you ˹truly˺ believe in Allah and what We revealed to Our servant on that decisive day when the two armies met ˹at Badr˺. And Allah is Most Capable of everything.
In practice, the share of the fifth reserved to the Prophet's family lapsed afterMuhammad's death.[1] The earlyRashidun Caliphs, notablyCaliph Omar, set down regulatory guidelines for what could and could not be regarded aswar spoils, and assigned the fifth for welfare distribution.[1] The 'fifth' eventually became an important source of financing for the Caliphal administration and army.Schools of Islamic law were divided on whether the fifth extended to treasure troves and mining. Some schools (notably, theHanafite), regarded treasure and mines as 'spoils' and thus subject to the fifth, while others (notably, theShafi'ite andHanbalite) regarded them as subject only to the conventional rates, e.g.zakat.[1]
The medievalTaifa kingdoms ofal-Andalus embraced the Hanafi argument and institutionalized the fifth on war spoils, treasure troves and mining.[2]
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In Christian kingdoms, the royal fifth partly comes from the medieval legal conception ofseigneural orregalian rights over the naturalpatrimony, which assigned to the monarch orfeudal overlord originalproperty rights over all unclaimed, undiscovered and undevelopednatural resources (e.g. precious metals in the subsoil, salt in the rock, virgin forests, fish in the sea, etc.) within his jurisdiction. Consequently, private individuals who extracted these natural resources owed compensation to their original 'owner', the monarch. It was adopted by the Christian states of theIberian Peninsula (Castile,Portugal, etc.) during thereconquista and extended to their overseas colonies in the Americas, Africa and Asia. They became an important part of crown finance.
During the age of exploration, Spanish and Portuguese captains andconquistadores were careful to always set aside the royal fifth from any spoils they captured, and accusations ofembezzling the 'royal fifth' ended the careers of a few of them (e.g.Alonso de Ojeda,Pedro Alonso Niño). Nonetheless, to encourage exploration and colonization, Iberian monarchs often allowed explorers and colonial developers to retain part or all of the royal fifth, for at least some period of time. The conditions were usually spelled out incaptaincy contracts or royal grants; e.g. in 1402,Jean de Béthencourt was allowed to keep the royal fifth as a condition for theconquest of the Canary Islands for Castile; in 1443, the Portuguese PrinceHenry the Navigator was granted the royal fifth on all enterprise in theMadeira islands and sub-Saharan Africa; in 1492,Christopher Columbus was allowed to retain 10% of the royal fifth of the West Indies (although he famouslyargued he was promised more); the 1532 contracts of the captains-donatary ofcolonial Brazil allowed them to retain 5% of the royal fifth.
In Spain, the quinto real onmining of precious metals was codified by the edict of February 1504 and (with occasional exceptional grants) remained in force through all the Spanish empire until the 18th century. In 1723, it was reduced to adiezmo (10%) and in 1777 it was reduced further to 3%, with an additional duty of 2% if shipped to Spain.[3]
Rather than levy the tax on the basis of the amount ofsilver orgold produced, the Spanish government tracked the amount ofmercury used. Mercury was essential for the refinement of silver and gold in thepatio process (see alsoamalgamation). The Spanish government had amonopoly of mercury production, through its mines atAlmadén in Spain and atHuancavelica inPeru. In 1648, theViceroy of Peru declared thatPotosí and Huancavelica were "the two pillars that support this kingdom and that of Spain". Moreover, the viceroy thought that Spain could, if necessary, dispense with the silver from Potosí, but it could not dispense with the mercury from Huancavelica.[4]