The yellowed, vacant stare of a human head encased in a glass cylinder at the Faculty of Medicine of the University of Lisbon serves as one of the most provocative intersections of criminal history and anatomical science in Europe. For over 180 years, this specimen has been attributed to Diogo Alves, a Galician immigrant who attained infamy as the "Aqueduct Killer". The head is described as having a "peaceful-looking" and "sarcastically calm" expression, which contrasts with the violent history attributed to it. This visual dissonance is part of what makes the object so compelling to the few members of the public who are permitted to see it. While not open to the general public, its presence is a well-known secret in Lisbon, occasionally entering the broader culture through photography and special exhibitions. The preservation of this head was not merely a macabre gesture but a deliberate act of 19th-century scientific inquiry, rooted in the now-debunked tenets of phrenology and the nascent field of criminal anthropology. However, the specimen presents a profound historical mystery: emerging research suggests a significant disconnect between the legendary narrative of the "Aqueduct Killer," the documented judicial reality of Diogo Alves, and the physical authenticity of the head itself.
 |
| Image credit: Utterly Interesting |
Historical and Socio-Economic Context of 19th-Century Lisbon
To understand the rise of a figure like Diogo Alves, one must examine the socio-economic conditions of Lisbon in the 1830s. Portugal was reeling from the aftermath of the Liberal Wars (1828–1834), a period of civil strife that left the national economy in shambles and the social order precarious. Diogo Alves, born in Galicia, Spain, around 1810, was part of a larger wave of migration from rural Spain to the Portuguese capital in search of labor. These migrants often filled roles as water carriers, servants, and coachmen—occupations that granted them intimate access to the households of the wealthy while keeping them tethered to the city's underclass.
Alves initially found work as a servant and coachman, positions that allowed him to observe the movements of the elite. His early years in Lisbon are poorly documented, but he is known to have been romantically involved with Gertrudes Maria, an innkeeper nicknamed "Parreirinha". This connection to the local innkeeping trade likely provided Alves with a network of information regarding travelers and their possessions, laying the groundwork for his transition into organized crime.
The Legend of the Águas Livres Aqueduct
The most enduring aspect of the Alves narrative is his association with the Águas Livres Aqueduct (Aqueduto das Águas Livres). This architectural marvel, completed in the 18th century, spans 941 meters and rises 65 meters (213 feet) above the Alcântara valley. In the 19th century, the walkway atop the aqueduct was a crucial transit route for farmers, traders, and washerwomen traveling from the outskirts to the city center to sell their goods.
The legend posits that between 1836 and 1839, Alves exploited this elevated walkway to conduct a series of horrific crimes. He allegedly intercepted victims at nightfall as they returned home with their day's earnings, robbed them, and then pushed them off the edge to their deaths. Because the fall was so great, the resulting injuries were indistinguishable from those sustained in a deliberate leap, leading authorities to initially classify the deaths as a sudden epidemic of suicides.
The scale of these alleged crimes is vast, with popular accounts claiming that Alves murdered between 70 and 100 people. This narrative suggests a level of predatory efficiency that would make him one of the most prolific serial killers in European history. According to folk history, Alves even acquired a master key to the aqueduct’s interior galleries, allowing him to bypass security and move unseen through the structure.
While the "Aqueduct Killer" legend is a staple of Lisbon folklore, modern historical scrutiny, most notably by researcher Miguel Carvalho Abrantes, reveals that this persona may be largely fictional. An analysis of contemporary court documents, including the public indictment (Libelo de Acusação Pública) and the 1840 court ruling (Acórdão da Relação), shows no mention of the Águas Livres Aqueduct or any serial murders.
The actual crimes for which Diogo Alves was apprehended and executed were committed in late 1839 and are collectively known as the "Rua das Flores Crime". Alves led a gang that broke into the home of Dr. Pedro de Andrade, a prominent physician. During the robbery, the gang murdered the doctor and four members of a family under his care: Maria da Conceição Correia Mourão, her son José Elias, and her daughters Emília and Vicência. A fifth victim, a servant named Manuel Alves, was killed to eliminate him as a witness.
The disconnect between the trial records and the popular myth suggests that the "Aqueduct Murderer" moniker emerged after Alves' death. It appears that Alves became a convenient scapegoat for a series of unsolved deaths—likely actual suicides or unrelated accidents—that had occurred at the aqueduct during a time of extreme social and economic distress. Municipal records indicate that deaths at the aqueduct continued until at least 1843, two years after Alves' execution, and the walkway was not fully closed until 1852.
The Science of the Skull: Phrenology and Anatomy
The decision to preserve the head of Diogo Alves following his hanging on February 19, 1841, was a direct consequence of the intellectual climate of the era. The mid-19th century was the height of phrenology, a pseudoscience developed by Franz Joseph Gall that proposed a direct relationship between the shape of the skull and the personality of the individual. Phrenologists believed the brain was composed of distinct "organs" responsible for traits such as "destructiveness," "acquisitiveness," or "benevolence".
To the medical community in Lisbon, Alves was a fascinating specimen of pure criminality. By severing and preserving his head, they intended to study the "bumps" on his cranium to identify the biological roots of his alleged cruelty. This was part of a broader European trend of building anatomical collections to study "monstrous" or "deviant" individuals.
The Faculty of Medicine's "Teatro Anatómico" became the repository for these specimens. Interestingly, there is little evidence that a formal phrenological study of Alves' head was ever published or completed. The head remained in its jar, moving from a subject of scientific inquiry to a permanent object of fascination and terror.
The Preservation Mystery: Formaldehyde vs. Spirit
One of the most compelling arguments against the authenticity of the "Diogo Alves" head involves the chemical process of its preservation. The head is currently submerged in a liquid identified as formaldehyde. This chemical is an extremely effective fixative that cross-links proteins, preventing cellular decay and bacterial growth.
However, historical records of chemistry indicate that formaldehyde was discovered by August Wilhelm von Hofmann in 1863, and its utility as a biological preservative was not identified until 1893. Since Alves was executed in 1841, the use of formaldehyde at the time of his death would have been anachronistic.
While it is possible that the head was initially preserved in a "spirit of wine" (ethanol) or a saturated salt solution and then transferred to formaldehyde decades later, such a procedure would be unusual and undocumented. Furthermore, the remarkable condition of the head—which still possesses realistic skin texture and hair—is more consistent with late 19th-century preservation techniques than with the cruder methods available in 1841.
The Identity Crisis and the 1978 Fire
The skepticism regarding the specimen’s identity is compounded by a catastrophic event in the history of the University of Lisbon. In March 1978, a massive fire destroyed the Polytechnic School building, which housed the National Museum of Natural History and various anatomical collections. The fire consumed the zoological section and, crucially, the museum's catalog system.
Without these original records, the identification of the head as "Diogo Alves" relies largely on institutional oral tradition. Historians like Abrantes suggest that the head currently on display may have been confused with another specimen over the course of 150 years. The head bears little resemblance to contemporary sketches of Alves made during his 1840 trial, which depict a man with different facial proportions.
Some theories propose that the head might actually belong to a different criminal or a subject of late 19th-century anthropological studies conducted by Francisco Ferraz de Macedo. The proximity of other specimens, such as the skull of Francisco Matos Lobo (executed in 1842), further complicates the potential for mislabeling during historical transitions of the collection.
The "Cabinet of Phrenology" at the University of Lisbon provides an excellent point of comparison through the remains of Francisco Matos Lobo. Lobo was a contemporary of Alves who committed a similarly high-profile quadruple murder and was executed a year after Alves in 1842.
Lobo’s remains consist only of a skull (identified as #2043 in research), which is a much more typical preservation for a mid-19th-century phrenological study. The fact that Alves was supposedly preserved as a full head while his contemporary was reduced to a skull is another anomaly in the narrative. If the faculty had the technology and desire to preserve a full head in 1841, it is unclear why they did not do so for other equally "fascinating" criminals of the same period.
Cultural Legacy and Media Representation
The transition of Diogo Alves from a historical criminal to a cultural icon was accelerated by early cinema. In 1911, the film Os Crimes de Diogo Alves was released, often cited as Portugal’s first fictional feature film. The movie synthesized the legend of the aqueduct with the Rua das Flores murders, effectively merging fact and fiction into a single, terrifying narrative for a 20th-century audience.
Alves has since appeared in comic books, television programs, and novels, usually portrayed as a ruthless, calculating serial killer. This cultural saturation has made it difficult for the public to separate the man from the myth. The preserved head acts as a physical anchor for this legend; as long as the head exists, the "Aqueduct Killer" remains a tangible presence in Lisbon’s history.
Ethical Considerations of Display and Research
The ongoing presence of the head in a medical faculty raises significant ethical questions regarding the display of human remains. In Portugal, the ethical debate on the use and exhibition of skeletal and soft-tissue remains is still in its nascent stages. While the scientific community values these collections for their biological data, the public perception is often divided between historical curiosity and moral discomfort.
Recent studies indicate that a majority of the Portuguese public is comfortable with the use of 3D replicas of human remains for educational purposes, which could eventually provide a way to retire the original specimen from display. However, the "celebrity" status of the Alves head makes it a unique case. Unlike the "now-anonymous men" in the skull collection, the Alves specimen is tied to a specific, if potentially inaccurate, biography that continues to generate tourism and media interest.
The Modern Synthesis: Fact, Fiction, and the Unresolved
In light of the 2025 research by Miguel Carvalho Abrantes, the "mystery" of the Diogo Alves head has shifted from a question of "why did he kill?" to "who is actually in the jar?". The evidence suggests three distinct possibilities:
- The Historical Anomaly: The head is indeed Diogo Alves, preserved by a precursor to formaldehyde or expertly transferred to the chemical later, with the 1840 sketches being poor representations of his true face.
- The Misidentified Specimen: The head belongs to a late 19th-century criminal (perhaps from the Macedo collection) whose identity was lost in the 1978 fire and replaced by the more famous name of Alves through oral tradition.
- The Composite Myth: The head is a collection of various 19th-century anxieties—about crime, about the "other" (the Galician migrant), and about the limits of scientific understanding—given physical form in a jar.
The resolution of the Diogo Alves mystery likely lies in modern forensic technology. DNA extraction and analysis could potentially link the specimen to known descendants of Alves or at least determine his regional origin (confirming or denying his Galician heritage). Furthermore, a chemical analysis of the preservation fluid and the deep tissue could determine if the head was ever subjected to pre-formaldehyde treatments, such as heavy metal salts or high-proof ethanol.
Until such definitive tests are conducted, the head of Diogo Alves remains a haunting emblem of 19th-century criminal justice and scientific curiosity. It sits at the nexus of several failed experiments: the failed social experiment of the aqueduct walkway, the failed scientific experiment of phrenology, and the failed archival experiment of the National Museum of Natural History. As a cultural object, however, it remains a resounding success, continuing to fascinate and terrify nearly two centuries after the man it supposedly represents was cut down from the gallows.
The preserved head of Diogo Alves represents more than the sum of its biological parts. It is a testament to a period when the human body was the primary map for understanding the human soul. The "mystery" of the head is a layer of historical insulation that protects the legend from the cold reality of the archives.
The specimen in the jar serves as a warning about the fallibility of institutional memory and the power of narrative over evidence. In the absence of a catalog, a name can be attached to any face, and in the presence of a legend, a single man can be blamed for an entire city's fears. Whether the eyes staring out from the glass are those of a Galician coachman or an anonymous 19th-century soul, they remain one of the most significant artifacts of forensic history in the world.
References:
Please don't put your website link in Comment section. This is for discussion article related only. Thank you :)