Silk raising in New Spain (the morales of the Mixteca and the Valle de Atlixco)
Mulberries and silkworms reached Mexico in the 1530s and were taken up so fast that a friar writing in 1540 named growers drawing three and four hundred pounds of raw silk. The trees stood on indigenous land, which is why a law of 1549 ordered the audiencias to stop encomenderos making Indians raise silk on their own morales. By 1748 an official found the industry gone from the Oaxacan town still called La Seda: the growers had killed the mulberries themselves.
Why this wins its question: Mexican silk is usually met as a sentence — "the Spaniards introduced silkworms to Oaxaca and the industry later declined" — with no text behind it and no indication of who owned the trees. Three printed sources are quoted here from the page instead: a Franciscan's pound figures for the 1540 season, a 1549 law whose opening clause states that encomenderos were forcing Indians to raise silk on mulberries standing on the Indians' own land and orders the audiencias to let them enjoy their holdings "como personas libres, y vasallos nuestros", and a royal cosmographer's 1748 report of an Oaxacan town still called La Seda where the growers had killed the mulberries because they expected to be preyed upon for prospering. The usual popular explanation — Chinese silk off the Manila galleon — is named and explicitly not asserted, because nothing opened for this entry supports it.
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 transfer was already productive within about a decade of the conquest. Motolinía, writing his Historia de los indios de la Nueva España by 1541, records in Tratado III capítulo VIII that in the mountain country "hay muchos morales y moreras; las moras que dan son muy menudas. Poco tiempo há que se dan á criar seda; dase muy bien, y en menos tiempo que en España."
The same passage gives the earliest quantities and a date. "Hay mucho aparejo para criar mucha cantidad andando el tiempo; y aunque se comienza ahora, hay personas que sacan trescientas y cuatrocientas libras, y aun me dicen que hay persona que en este año de 1540 sacará mil libras de seda." The friar adds that some of what has been drawn has been dyed, "y sube en fineza; y metida en la colada no desdice por la fineza de las colores" — the last clause is a claim about the local dyes, not about the silk alone.
In a passage written from the Puebla side, Motolinía names the mulberry as the most profitable planting of the valley the Spaniards called Val de Cristo, four leagues from the city: "lo que mas ricas hace estas heredades son los morales que tienen puestos y ponen cada dia, porque hay muy grande aparejo para criar seda" (Tratado III, capítulo XVIII). The chapter is the same one in which he reports that men who know land judged the vega of Atlixco better than the vega of Granada.
Elsewhere the friar is careful to say the industry was still small when he wrote, and to describe its quality rather than its volume: "La seda que en estas partes se hace, aunque hasta ahora es muy poca, es tan fina que aunque la echen en colada fuerte no desdice" (Tratado III, capítulo XV). Read together with the thousand-pound figure, this is a witness describing a young industry that was growing while he was writing, not a settled one.
The mulberry trees were on indigenous land and the silk was an indigenous grangería, which is the premise of the law that protected it. Recopilación de leyes de las Indias, libro VI, título V, ley xxxxviiij — "Que los Indios no reciban agravio en pagar mas de sus tasas, ni en sus grangerías", attributed to the Emperor Charles and the governing monarchs of Bohemia at Valladolid on 22 June 1549 — opens: "LOS Encomenderos de Nueva España, demas de los tributos que perciben, hacen que los Indios les crien seda, valiéndose de los morales que tienen en sus tierras, en que reciben perjuicio, y daño, quitándoles sus frutos, y grangerías."
The remedy in the same law is a general one about economic liberty rather than about silk: "Mandamos que nuestras Audiencias pongan el remedio que mas convenga, y hagan de forma que los Indios no sean agraviados, y gocen de sus haciendas libremente, sin estorbo en sus grangerías, y aprovechamientos, como personas libres, y vasallos nuestros." The clause is printed in a título about tributes and assessments, immediately after laws forbidding encomenderos to take anything beyond the assessed tribute.
A place name survived the industry. José Antonio de Villaseñor y Sánchez, cosmographer of the realm, in the Theatro americano (Mexico, 1748), libro quarto, capítulo IV, on the jurisdiction of Guejolotitlán in Oaxaca: "Toca à este Partido el Pueblo nombrado la Seda, en el qual antiguamente avia crecida copia de enxambre de gusanos de seda, cuyo beneficio daba notable utilidad, no solo â esta Jurisdiccion, sino á la Region mysteca su vecina, de donde tomò nombre la Seda, assi llamada, y con la seda de esta cria esmaltaban sus ropas de algodon los antiguos."
The same sentence gives the collapse and two causes, one of them the growers' own decision. Villaseñor continues that it seemed to the inhabitants "que por desfrutar el beneficio de este noble capullo, avian de ser percegidos", so that "no solamente suspendieron la cria del enxambre, sino que inutilizaron los morales de su sustento"; and that "oy ay muy poca, à causa de averse destinado los Indios à otras haciendas, como son las de grana, mayces, y algodon". Prosperity understood as a summons to be preyed upon, and labour reallocated to other crops, are printed side by side by an official of the government that reallocated it.
The witness's contempt is part of the evidence and is left standing here. Villaseñor calls the people who abandoned the industry "sus cerriles habitadores" — its uncouth inhabitants — in the middle of the clause reporting that they feared persecution if they prospered. A reader is entitled to weigh that fear against the record of forced rearing in the 1549 law rather than against the surveyor's adjective.
What these three sources cannot establish is as important as what they do. None of them says who first brought mulberry seed or worms to New Spain, or in what year; none gives an output series; and none of them names Chinese raw silk arriving through the Manila trade, which is the explanation most often given for the decline of Mexican sericulture. The compressed arc available from the page here is that the industry existed and was indigenous-held by 1540, that it was being extorted by 1549, and that by 1748 an official could find it reduced to a village name — not a demonstration of what killed it.