Giuseppe Fiorelli (1823–1896) was the senior Italian archaeologist of the second half of the 19th century — the man who took the chaotic Bourbon-era treasure-hunting site of Pompeii and turned it into the founding methodological example of modern stratigraphic archaeology. He had been a Neapolitan numismatist (a specialist in ancient coinage) before being appointed director of the Pompeii excavations in 1863, age 40, by the new Kingdom of Italy government. He ran Pompeii for twelve years, founded the Italian National School of Archaeology in 1875, and became Director-General of the Italian National Antiquities Service in 1875.
His central innovation was procedural rather than spectacular. The Bourbon-era excavation of Pompeii (1748–1860) had been driven by treasure recovery — finding and removing decorative items, sculptures, and wall paintings for display in the Naples royal collection, with minimal documentation of where the material had come from or how it related to the surrounding context. Most of the Bourbon excavation work had been backfilled after the removable material had been extracted; the site was a patchwork of partly-excavated areas with no coherent map and no systematic record.
Fiorelli’s first decision in 1863 was to stop the backfilling. Excavation would proceed by removing entire blocks of the buried city in horizontal stratigraphic layers, with detailed photographic and drawn documentation of each layer before the next was removed. The exposed structures would be left in situ and stabilised against further weathering. The recovered moveable objects would be catalogued by find-spot and held at a dedicated on-site museum rather than being removed to the Bourbon collection.
His second decision was to organise the site geographically. The Bourbon excavators had identified buildings by the names of contemporary aristocratic patrons (the House of Caligula, the House of the Emperor, the House of the Faun) rather than by location. Fiorelli divided the city into nine regiones (administrative regions), subdivided each regio into insulae (city blocks), and gave every building a three-number address (Region.Insula.Building). The Fiorelli numbering system is still the standard reference system for Pompeii: the House of the Faun is VI.12.2 (Region VI, Insula 12, Building 2). The system has been extended to subsequent excavations at Herculaneum and Oplontis.
His third decision was the famous one. The plaster casts.
The plaster-cast technique
The pyroclastic material that buried Pompeii in 79 AD had a critical mechanical property: it had set hard around organic objects (human bodies, wooden furniture, food remains) at the time of deposition, then preserved the impression of those objects as a hollow cavity after the original organic material had decayed away over the following nineteen centuries. The bodies of Pompeii’s eruption victims had decomposed inside their hardened-ash envelopes, leaving precise full-body impressions in the surrounding tuff.
The Bourbon-era excavators had repeatedly broken into these hollow cavities — sometimes recovering loose bones, more often destroying the cavity without recognising what they were destroying — without any systematic technique for documenting them.
Fiorelli’s idea, developed in early 1863, was to pour liquid plaster of Paris into any cavity encountered during excavation, wait for the plaster to set, and then carefully chip away the surrounding tuff to expose a plaster cast of whatever had originally occupied the cavity. The technique was first applied on 5 February 1863 to a cavity encountered in the Vicolo degli Scheletri (the Alley of the Skeletons) near the city’s east gate, which produced a plaster cast of three adult human bodies — two adults huddled together, a child between them — preserved at the moment of their 79 AD death.
The casts were extraordinary. The plaster captured the precise body posture (the protective curl, the raised arm, the cloth folds of clothing), facial features (the open mouth, the closed eyes, the visible expression of fear), and small physical details (a leather sandal strap, a coin pouch at the waist, a hair ornament) of the original victims. Loose skeletal material from inside the cavity was incorporated into the cast and is visible in cross-sections of the older specimens.
The technique was iteratively refined through the 1860s and 1870s. Approximately 100 plaster casts of human victims were made during the Fiorelli directorship, and a further several hundred over the following century. The casts of dogs, horses, and food items were added to the corpus in the 1870s. The technique was extended to root cavities by the American archaeologist Wilhelmine Jashemski in the 1960s and 1970s, producing plaster reconstructions of Pompeii’s ancient gardens at root-system level — a contribution that allowed the systematic botanical reconstruction of the city’s ancient plant life.
The methodological influence
Fiorelli’s stratigraphic-recording technique and his geographic numbering system became the foundational method for the entire late-19th-century European archaeological tradition. His National School of Archaeology at Pompeii (founded 1875, located in a small building inside the excavated city) was the first formal training institution for stratigraphic field archaeology anywhere in the world; the school produced the first generation of methodologically-trained Italian field archaeologists (Giulio De Petra, Antonio Sogliano, Vittorio Spinazzola), most of whom went on to lead excavations elsewhere in Italy through the 1880s and 1890s.
The British and German archaeological communities adopted the Fiorelli stratigraphic method through the 1870s and 1880s. Augustus Pitt Rivers’s English work at Cranborne Chase (1880s) was substantially shaped by Pitt Rivers’s 1875 visit to Pompeii and his direct study of Fiorelli’s recording methods. Heinrich Schliemann’s later (post-1880) excavations at Troy and Mycenae adopted the stratigraphic principles although Schliemann had famously not applied them to his earlier and most-famous Trojan campaigns. The American tradition (founded by the Harvard Peabody Museum in the 1880s and 1890s) was based directly on the Pompeii model.
The Fiorelli plaster-cast technique was widely admired and rarely imitated, partly because no other major archaeological site has the specific combination of organic-preservation-by-pyroclastic-cavity that Vesuvius produced at Pompeii. The closest comparable application was the Pleistocene casts of human and animal footprints in pyroclastic ash at Laetoli (Tanzania, c. 3.6 million years old), where the same physical principle had operated at a substantially longer time-scale. The Laetoli casts were made in the 1970s by the Mary Leakey palaeoanthropological team using a substantially-modernised version of the Fiorelli technique.
The Pompeii he left
Fiorelli stepped down from Pompeii in 1875 to take the national Antiquities Service directorship. The Pompeii he left to his successors had been excavated to approximately a third of its total city area, was comprehensively catalogued, and had an established on-site documentation infrastructure. Subsequent directors — most notably Amedeo Maiuri, who ran the site from 1924 to 1961 — extended the excavated area to approximately two-thirds of the city, built the modern Pompeii museum at the site’s western entrance, and consolidated the Fiorelli stratigraphic method as the global standard for excavation of buried-city sites.
The Fiorelli plaster-cast technique remains the iconic technique of the site. The recovered casts — approximately 100 from the Fiorelli period, several hundred more from the subsequent century, several dozen new ones from the 21st-century continuing excavations — are displayed in glass cases at the Pompeii on-site museum, the Naples National Archaeological Museum, and at the various individual house locations where they were originally recovered. They are among the most-photographed artefacts of any classical archaeological site.
The casts substantively recover the moment of death of the people they preserve. The protective curl of the parent. The reach of the child. The horse pulling against its halter. The dog twisting against its chain. A 19-year-old archaeology summer student in 1863 named the alley they came out of Vicolo degli Scheletri — the Alley of Skeletons. The name is on the modern site maps. The original three casts from the alley are in the Naples museum, in a small dedicated room, with a placard giving the date the plaster was poured (5 February 1863), the find-spot Fiorelli reference (VI.13.something), and the conjectural identifications (mother, father, child) that Fiorelli proposed for them at the time of the discovery.