# Diego Alfonso de Medrano

Diego Alfonso de Medrano (Logroño, 16th century – 17th century) was a noble from the House of Medrano and a prominent alchemist tried by the Spanish Inquisition during the Spanish Renaissance. He practiced alchemical medicine in Madrid, collaborating with many of the city's leading physicians, distillers and apothecaries. Medrano worked within an environment of alchemy that prospered at the Spanish court. He was the tutor of the Duke of Infantado.

## Life and background

Don Diego Alfsono de Medrano was from the important and noble House of Medrano in Logroño, La Rioja. Pedro de Toledo Osorio, II Duke of Ferdandina was the patron of Diego Alfonso de Medrano. Medrano's wife was a wealthy Sicilian noblewoman and it is possible that she may have connected him with alchemists of Italian origin in Aranjuez. Pedro de Toledo Osorio, II Duke of Ferdandina was also the 5th Marquess of Villafranca del Bierzo, Governor of the Duchy of Milan, Prince of Montalbano, a Spanish-Italian nobleman and a Grandee of Spain.

### Education

Diego Alfonso de Medrano was an established nobleman and in his home town of Logroño he initially started his study of alchemical medicine. His method of crafting medicines was scholarly, deeply rooted in the traditional alchemical and hermetic literature that utilized a complex language of emblems, mystical symbols and allegories to decipher medical secrets. Diego Alfonso de Medrano's practice of alchemical medicine was supposedly linked with astrology and 'magic'.

### Tutor to the Duke of Infantado

Diego Alfonso de Medrano served as the tutor to Íñigo López de Mendoza y Mendoza, 5th Duke of the Infantado during the latter half of the 16th century. His position as the Duke's educator solidified his ties with the court's noble and scientific circles, which included many Italians. Diego's teachings to the Duke encompassed a variety of subjects, astrology among them. Valerio Forte, the chief distiller for King Philip III of Spain, provided Medrano with an astrology book, which Medrano utilized in his capacity as a tutor to the Duke of Infantado.

## Trials in the Spanish Inquisition

Prior to Diego Alfonso de Medrano's trial in 1611, he faced trial in 1601 for having previously been found guilty of sorcery in his hometown of Logroño.

### Medrano's first trial (1601)

A summary of the first case (relación de causa) still exists within the archives of the Suprema. Records indicate he was accused of:
   ...having made many sigils of different metals and many clay and wax figurines of men and women, all pertaining to Santa Maria...

### Sentenced to the Galleys of Spain (1601)

The summary forwarded to the Suprema revealed that the inquisitors in Logroño had subjected Diego Alfonso de Medrano to torture, including the rack and garrote, compelling him to confess to creating sigils, engaging in judicial astrology, and holding banned books. Following a protracted trial with fifty-five witnesses, the Inquisition branded him a heretic, they banished Medrano and condemned him to 10 years in the galleys of the king. Later on, when inquisitors from Toledo sought details of this trial from their counterparts in Rioja, an inquisitorial familiar exaggeratedly described Diego Alfonso de Medrano as "in the field of sorcery, lies, and demonic dealings [Medrano] must be the most notable delinquent in the entire kingdom."

### Return to Madrid (1606)

Diego Alfonso de Medrano ultimately spent only five years as an oarsman on the King's galleys. By around 1606, while he was in Madrid awaiting his subsequent assignment "with much clemency," the Inquisition showed considerable leniency by converting his galley sentence into additional years of exile. Despite this ban, he soon settled in Madrid, positioning himself as an expert in alchemical medicine and aligning with some of Madrid's leading doctors, pharmacists, and distillers.

### Medrano's second trial (1611)

Diego Alfonso de Medrano faced trial under the Toledo Inquisition for supposedly having a pact with a demon. In February 1611, the Inquisition took Medrano into custody. Pedro García, the inquisitorial familiar responsible for his arrest, later reminisced about the moment he approached Medrano on the Duke of Infantado's staircase, noting how Medrano's complexion turned pale, and he supposedly wore an expression of guilt. During the arrest, García discovered an empty glass vial and a copy of "The hundred conclusions and method of knowing the true skill founded on science" by Luís Pacheco de Narváez on Medrano. García detained Medrano, escorting him to the Inquisition's jail where he would stay pending his trial in July.

#### Testimonies

A notable individual who spoke in support of Medrano during his trial in 1611 was Valerio Forte, the chief distiller (destilador mayor) for Philip III. Valerio Forte acknowledged that he had provided Medrano with an astrology book, which Medrano utilized in his capacity as a tutor to the Duke of Infantado. Medrano also received support during his trial from medical practitioners, among them an apothecary and a distinguished physician who had his practice on San Bernardo Street, known as Doctor Lara.

#### Clerical evaluation

In the period of late March and early May 1611, Inquisitors dispatched portions of the texts seized from Diego Alfsonso de Medrano to three different monasteries for evaluation. A parcel, marked March 23, was directed to San Pedro Mártir in Toledo, another was sent on May 2 to Fray Hernando de Tobar at San Bernardo, and a third on May 9 to Estevan de Oxeda and Rodrigo Nino. The file includes critiques from the first two monasteries, which found Medrano's writings to be heretical. Both reviews denounced Medrano's works, with the first one being fairly brief, stating that Diego Alfonso de Medrano's compositions "speak of sigils and contain much superstition." The friar from San Pedro Mártir, who examined the documents, observed that one of Diego's papers "contained an ensalmo that seems to indicate an implicit pact with the devil." The second evaluation by Fray Hernando de Tobar was extensive and more detailed.

### Medrano's defense (1611)

Diego Alfonso de Medrano was given a chance to defend himself. In his submission to the inquisitors, Diego launched a vigorous defense of his integrity while sharply criticizing his adversaries, whom he argued provided evidence that was unreliable due to their prejudice. Despite being labeled a converso by the prosecutor, Medrano firmly maintained his status as an Old Christian of a distinguished noble lineage along with his connections of the scientific elite in Madrid, especially Valerio Forte. Diego singled out his antagonists as "anyone from Logroño" and, more specifically, targeted his "mortal enemy" Juan de Ibañez, accusing him of having an affair with his wife. This conflict with Ibañez escalated into a violent sword fight, leading to Diego facing criminal charges and subsequently being ordered by a Valladolid chancery judge to leave the capital, a verdict that severed his ties with his wife and diminished his esteemed position in Madrid.
Diego explained that the President of the Council of Castile, Pedro de Galeas, had helped him secure royal approval to return to court. However, once back, his adversaries saw an opportunity to extort him, seizing his notebooks and blackmailing him with a hefty fee he couldn't afford, under the threat of turning him in to the authorities. When accused of improperly using astrology and creating unauthorized sigils, he stated that he had abandoned such practices after leaving Logroño, noting that carrying on without the required astrological texts was out of the question. He tried to shift the fault to Carmona, math teacher of the monarchs, accusing him of being an unproductive troublemaker with the necessary books for judicial astrology. Medrano also dismissed allegations of practicing lapidary magic and shared that his conversations about using stones were concurred with by the cantor of the royal chapel, who also didn't view them as superstitious.

#### The Philosophers' stone

During the trial, Diego Alfonso de Medrano additionally referenced a method he discovered in a book written by Isabella Cortese, her modern book of secrets, which recommended using lead as a substitute for antimony. Medrano provided more details, explaining the eight alchemical processes and the various substances (including medicinal concoctions) that resulted from them. Medrano asserted that this process ultimately brings forth the end result "with the property to transmute metals and human bodies." Diego clarified that these processes were also known by esoteric titles, which the Spanish Inquisition mistakenly construed as heretical commentary on the human body's structure. Diego Alfonso de Medrano revealed to the inquisitors:
   [This] explains the two ciphers of the Philosopher's Stone under the name of ‘man’ and not ‘man’ as in human, which only consists of body and soul.
Responding to the allegation that human beings consist of three or more substances, Medrano offered deep insights into his approach as both a healer and alchemist. He clarified that his notebook entries on the triad of human elements—body, mind, and soul—were in fact an alchemical allegory.
He pointed out that alchemy was intentionally obscure, demanding the decoding of multiple layers to grasp the essence used in metal transmutation and medicine creation. Medrano indicated that any mention of human composition in his writings actually refer to the Philosophers' Stone, with "body, mind, and spirit" representing sulfur, mercury, and salt. He explained that these elements themselves were allegorical, with the true components of the Philosophers' Stone being gold, antimony, and quicksilver. Medrano maintained that this method of representing the three elements was widely used by scholars, backing his argument with references to a variety of authoritative sources:
   All of the books by the philosophers agree that the [Philosophers'] stone consists of body, soul, and spirit, which is composed of the said minerals, gold, antimony, and mercury or quicksilver, reduced in liquors in order to unite and mix them, and the authors of this are, Ramon Llull, Johannes de Rupescissa, Arnau de Vilanova, Morieno, Albertus Magnus, Avicenna, Al-Razi, Aristotle (De Perfecto magisterio, a thirteenth-century work misattributed to Aristotle), Joanes and Saalo Olando, and the authors get those three substances from the authors of Theatrum Chemicum, Turba Philosophorum, Margarita preciosa, and Roger Bacon; Johannes Anglicus and Andreas Libavius the doctor put certain hieroglyphics on the Philosopher's Stone of body, soul, and spirit, painting a crowned king, and Geber the philosopher speaks of this; all of them write in a way that is veiled and covered under diverse names.

### Medrano's sentence (1611)

In July 1611, the Toledo tribunal's prosecuting attorney charged Diego Alfonso de Medrano, known for distilling alchemical medicines, with supposedly being in a pact with a demon. Despite the support of Diego Alfonso de Medrano's powerful associates, inquisitors found him guilty and sentenced him to pay a fine of 30,000 maravedís, receive two hundred flagellations, and face lifelong seclusion in either a hospital or a monastery.