Gunpowder Magazine of the Knights in Rhodes

Identity

Site & dates

Arsenal complex › Argyrokastrou Square, north-western Collachium

Stands at the northern end of the west range of Argyrokastrou Square, within the Arsenal (Armoury) complex that occupied this corner of the Collachium from at least the fourteenth century — immediately north of the Naval Arsenal, and closed on the square’s east side by the Inn of the Tongue of Auvergne. The magazine building itself is never dated by its own heraldry, inscription or documentary reference; its construction can only be placed within the wider complex’s multi-phase development, below.

14th–16th c.

The magazine’s own construction date is not independently established; it falls somewhere within the Arsenal complex’s broad multi-phase development, from a fourteenth-century core to an early-sixteenth-century remodelling.

1454–1476

The adjoining Armoury storehouse, immediately south of the magazine, is dated by the jointly carved arms of Grand Masters Jacques de Milly and Giovanni Battista Orsini — the chamber known today as the Armoury (Oplothiki) De Milly.

Grand Master Giovanni Battista Orsini, portrait

1489–1521

The Order’s Old Hospital, within the same complex, is incorporated as a cannon workshop after 1489; its east front is remodelled under Grand Master Fabrizio del Carretto, 1513–1521.

Grand Master Fabrizio del Carretto, portrait

1522

Rhodes falls to Suleiman the Magnificent; the magazine’s reported — and allegedly falsified — powder stocks are directly implicated in the Order’s decision to accept a negotiated surrender.

1948 – today

The wider Arsenal complex becomes the Municipal Art Gallery of Rhodes, founded that year by Andreas Ioannou, Prefect of the Dodecanese, together with the Folk Art and Folklore Museum of the Dodecanese.

Warfare

A shift in warfare

1453–1522 › gunpowder forces a redesign of siege and fortification alike

For over a century after their first attestation, firearms remained a marginal presence in battle rather than a decisive one: early cannon were forged, not cast, in iron — heavy, difficult to manoeuvre, mounted without wheeled carriages, slow to reload. The change, when it came, was abrupt and total: in the words of this project’s own source for the period, it was “an inevitable revolution in the common tactics of war and, consequently, of the ancient techniques of defence.” Systems of urban and military defence that had changed little in essentials since Roman times were suddenly inadequate, and European military architecture would be reshaped, continuously and urgently, in direct response.

Constantinople, 1453

Sultan Mehmed II’s siege train of some 68 Hungarian-cast cannon — the largest reportedly 26 feet long and firing stone shot of up to 1,200 lbs — battered down the thousand-year-old Theodosian walls in 55 days, bringing about the fall of the Byzantine capital. The same Ottoman artillery tradition besieged the Knights’ Rhodes in 1480 and took it in 1522.

Monastery wall painting depicting the 1453 Ottoman siege of Constantinople

From a marginal weapon to a decisive arm, by 1494

Charles VIII of France invaded Italy with cannon cast in bronze rather than forged in iron, firing shot in iron rather than stone, mounted on carriages that made them far more transportable, more powerful, and markedly faster to reload — a new generation the Italian states could not match.

The corner bastion, from the 1480s

The general European pattern by which gunpowder artillery forced a fundamental redesign of fortification — walls and towers built lower and wider, and the geometric, corner-bastion system of so-called “Italian tracing” emerging specifically to resist and deflect cannon fire — is concretely attested at Rhodes within a few years of the Armoury storehouse’s own completion.

The Bastion del Carretto, one of the corner bastions of the Rhodes fortifications

Rhodes rebuilds, 1480–1522

Ottoman gunpowder artillery left Fort St Nicholas “almost demolished” in the 1480 siege; Grand Master Pierre d’Aubusson answered with a new, gun-resistant outer bastion, accepted in 1482. The Vicentine military architect Basilio della Scola is separately recorded as “a fortifier of Rhodes and also a skilled artillerist, as was then customary,” before entering the service of Charles VIII of France — a single, if isolated, named link between the two.

Illuminated manuscript depicting the 1480 siege of Rhodes and the defence of the harbour, including Fort St Nicholas (Bibliothèque nationale de France, Latin 6067)

Function

A revolution in storage

14th–16th c. › gunpowder, and a new kind of building

Gunpowder — a ground and sifted mixture of saltpetre, charcoal and sulphur, its proportions only definitively fixed at the end of the sixteenth century as six parts saltpetre to one part each of the other two — had been known in Europe since at least the fourteenth century, at first mainly for pyrotechnic display, before its offensive military use spread from that same century onward. The wider tactical revolution this forced, discussed opposite, supplies the essential context for the Order’s own investment at Rhodes in the purpose-built military-logistics infrastructure that keeping and supplying its artillery required — the gunpowder magazine among it.

Saltpetre, the hardest to find

At first gathered as a natural efflorescence in damp cellars and caverns, and only later produced deliberately in dedicated nitrification beds, from soil rich in organic waste diluted with water and decanted in boilers.

Dry, ventilated, spark-free

The finished powder itself required storage conditions a small, thick-walled, vaulted, largely windowless chamber met well — the specific technical demand a purpose-built magazine, rather than any ordinary storeroom, was designed to answer.

A building defined by function

Unlike the decorated civic and defensive monuments elsewhere in the Collachium, the magazine carries no sculpted heraldry or ceremonial programme — its plain, thick-walled form is dictated entirely by the technical needs of powder storage.

Part of a wider logistics quarter

The magazine belongs functionally to the Order’s wider fourteenth- to sixteenth-century development of Argyrokastrou Square as a naval and military logistics quarter, confirmed in operation by contemporary testimony and by the miniatures of Guillaume Caoursin’s chronicle (Ms. Par. Lat. 6067).

Fabric

What survives

Argyrokastrou Square › a plain, thick-walled chamber within a working arsenal

The magazine is a compact, almost square, tower-like structure rising above the roofline of the buildings around it, entered by a single low door on its south side. Its walls are thick and otherwise unbroken, pierced only by one small window set high on the east side and by scattered small rectangular ventilation openings; internally it is roofed by a ribbed cross-vault — mass, near-blindness and controlled ventilation, together, doing the work that gunpowder storage required.

The windowless chamber

Thick, largely unbroken walls and minimal fenestration distinguish the magazine sharply from the more decorated civic and defensive monuments documented elsewhere in the town.

The Armoury storehouse of de Milly and Orsini

Immediately south of the magazine stands the sole survivor of a pair of long, vaulted storehouses that made up the Knights’ Armoury proper, carrying the jointly carved arms of Grand Masters Jacques de Milly and Giovanni Battista Orsini; its companion, further west near the modern Gate of Liberty, survives only as the springing of a vault high on the wall.

The del Carretto doorway & the Old Hospital

South again, the Order’s former First (Old) Hospital was absorbed into the Armoury after 1489 as a cannon workshop; its chapel apse was demolished and replaced by a doorway during the magistracy of Grand Master Fabrizio del Carretto, whose own coat of arms, set high above it, dates the remodelling.

Materials & construction

Coursed masonry with dressed stone at doorways and vault springers, roofed throughout in stone vaulting — a ribbed cross-vault over the magazine chamber itself, distinguished within the range by its thicker, largely unbroken walling.

History

Persons & events

1355–1948 › from a Grand Master’s arsenal to a civic gallery

None of the figures below is tied to the magazine building’s own fabric by heraldry or inscription; most are associated with the wider Arsenal complex within which it stands, though d’Aubusson, l’Isle-Adam and d’Amaral connect directly to the magazine’s documented function during the 1522 siege.

Roger de Pins, Grand Master 1355–1365

Under whose magistracy the wider Arsenal complex at Argyrokastrou Square is recorded as having been built; his arms are recorded on the complex, though not specifically tied to the magazine.

Jacques de Milly & Giovanni Battista Orsini, Grand Masters 1454–1476

Their arms, carved jointly on the surviving Armoury storehouse immediately south of the magazine, give the chamber its modern scholarly name.

Jacques de Milly, Grand Master 1454–1461

Giovanni Battista Orsini, Grand Master 1467–1476

Pierre d’Aubusson, Grand Master 1476–1503

Successfully defended Rhodes against Mehmed II’s siege of 1480; his defiant answers to the Ottomans’ offer of peace are the historical counterpoint to the negotiated surrender of 1522.

Fabrizio del Carretto, Grand Master 1513–1521

His coat of arms dates the remodelling of the Old Hospital’s square-facing side, within the same Arsenal complex.

Philippe Villiers de l’Isle-Adam, Grand Master 1521–1522

Ordered the 1521 inspection of the Order’s magazines; directed the emergency grinding of fresh saltpetre using his own stable horses during the 1522 powder shortage; accepted the citizens’ petition to surrender.

Andreas d’Amaral, Grand Chancellor

One of three grand crosses who inspected the magazines in 1521; convicted by his own brother knights of treasonable communication with the enemy and, on one strand of tradition, of falsifying the magazine’s own powder report; executed 7–8 November 1522. His guilt remains debated.

Andreas Ioannou, Prefect of the Dodecanese

Founded the Municipal Art Gallery of Rhodes in 1948 within the former Arsenal complex, the civic use it retains today alongside the Folk Art and Folklore Museum of the Dodecanese.

Testimony

Eye witness: the treason of 1522

1480–1522 › defiance, betrayal, and a negotiated surrender

Grand Master Pierre d’Aubusson, defiance, 1480

When a Turkish envoy proposed a negotiated peace during the first siege, d’Aubusson answered that “men who were not afraid of death, were a much stronger fortification than walls and bastions” — and warned his own knights that “if you think fit to stay with us, speak not a word more about a composition, for if you do, your lives shall pay for it.”

Vertot, The History of the Knights Hospitallers of St. John of Jerusalem, vol. III (1757 English edition).

The Grand Chancellor’s trial, 1522

Andreas d’Amaral was arrested on 30 October 1522 and tried for “treasonable communication with the enemy.” He refused to confess even under torture, was found guilty by his own brother knights, stripped of the Hospitaller habit in the church of St John, and executed on or about 7–8 November 1522.

Kenneth M. Setton, The Papacy and the Levant (1204–1571), vol. III (Philadelphia: American Philosophical Society, 1976).

Grand Master l’Isle-Adam, on the surrender, 1522

Citing “the lack of men, powder, munitions, and even hope” as the reason the Order finally accepted terms — a chronic and worsening shortage of powder, worsened, on this project’s principal narrative source, by d’Amaral’s false report to the council that the magazines held enough for a year.

Quoted in Setton, The Papacy and the Levant, vol. III, 1976.

Jacques de Bourbon, French knight, eyewitness, 1522

Writing within two months of the siege’s end, records that the town’s own citizens petitioned the Grand Master to surrender because “provisions and men were failing.”

Letters and Papers of Henry VIII, 1521–1523; reproduced in Simon David Phillips, PhD dissertation, National and Kapodistrian University of Athens, 2021.

A postscript, unverifiable: the explosion of 1856

More than three centuries after the siege, on 9 November 1856, a catastrophic explosion tore through the city of Rhodes. It is recorded as having originated in the crypt of the church of St John of the Collachium, immediately adjacent to the Palace of the Grand Master, where quantities of gunpowder stored there since the Knights’ own tenure — kept, on this account, against the threat once posed by Suleiman the Magnificent’s forces — are said to have detonated, with heavy loss of life. Popular tradition in Rhodes has long asked whether this was in some way the same powder at issue in 1522: whether stores d’Amaral was accused of concealing, or of falsely reporting as sufficient, went undiscovered and forgotten for three hundred years rather than exhausted in the siege. No source reviewed for this document establishes any such continuity, and none can: the 1522 magazines, this building among them, are not documented as the source of the 1856 powder, nor is any direct chain of custody recorded across three centuries. The connection belongs to popular memory rather than to established history — a resonant local legend, not a verified fact, and it is presented here as exactly that.

On the 1856 explosion: standard local and touristic histories of Rhodes; on its evidentiary limits with respect to 1522, no primary source reviewed for this document. Unverified tradition, reported here as such.

Gallery

Photo gallery

Twelve views › the magazine’s blank walls and Arsenal courtyard, with three period-manuscript folios and the 2025 study visit for context

Assessment

Significance criteria

Nine-criteria framework › National to international importance

Rarity

A comparatively rare survival: functional military-logistics buildings of this kind are more vulnerable to demolition, conversion or unrecorded loss than the monuments they once supported, and comparable powder stores elsewhere on the fortifications have not been located or have been destroyed.

High

Representativeness

Highly representative of the Order’s practical, technical response to the gunpowder revolution in European warfare — a response usually illustrated by artillery-resistant towers and bastions, but equally dependent on unglamorous supporting infrastructure of exactly this kind.

High

Aesthetic value

Designed for function, not display: blank, thick walls and minimal fenestration carry no sculpted heraldry, inscription or decorative programme. Its interest lies in the legibility of its purpose-built form rather than in any ornamental quality.

Low

Integrity

Genuinely unassessed: the sources reviewed do not establish whether the magazine’s fabric survives intact or has been altered by the same later interventions documented for neighbouring parts of the complex, and no dedicated structural survey is known.

Uncertain

Historical value

Exceptional: this project’s principal narrative source connects the magazine’s own reported contents directly to the proximate cause of the Order’s loss of Rhodes in 1522 — the chronic powder shortage, worsened by d’Amaral’s alleged false report, corroborated in broad outline by Setton’s academic account and by a contemporary eyewitness.

Exceptional

Symbolic, spiritual & social value

Substantial: on the tradition recorded in this project’s sources, the magazine’s own reported contents became a material fulcrum in the Order’s decision to accept surrender, standing in stark contrast to the Order’s successful defence of the same city in 1480.

High

Scientific value

Substantial, currently unrealised research potential: the magazine’s own construction date, its structural relationship to the dated Armoury storehouse and Old Hospital immediately adjoining it, and its post-1522 history are all open questions.

High

Interpretive potential

Substantially enhanced by its connection to one of the most consequential episodes documented anywhere in this project: the treason of Andreas d’Amaral and the negotiated fall of Rhodes, presented in instructive contrast to the Order’s valorous defence of 1480.

High

Importance level

A contributing component of the UNESCO-inscribed Medieval City of Rhodes, protected under Greek Archaeological Law, and the material locus of a single episode of European as well as Rhodian historical consequence.

National–International

Statement of significance

“The lack of men, powder, munitions, and even hope.” (Grand Master Philippe Villiers de l’Isle-Adam, on the reasons for the surrender, December 1522.)

The Gunpowder Magazine is a compact, purpose-built ordnance store at the northern end of the west range of Argyrokastrou Square, distinguished from its neighbours by its thick, largely windowless walls and minimal, carefully placed ventilation — a rare and legible surviving example of the specialised military-logistics architecture the Hospitaller Order’s adoption of gunpowder artillery required. Its documented function, by contrast, is directly and dramatically attested: this project’s sources connect its own reported powder stocks to the treason of Grand Chancellor Andreas d’Amaral and to the negotiated fall of Rhodes in December 1522. This significance must be assessed together with an honest acknowledgement of how little is independently established about the magazine building itself, as distinct from the wider complex in which it stands: its own construction date, its structural integrity, and its post-medieval history are all open questions on the sources reviewed for this document. Any conservation, research or interpretive use of the building should treat these as genuine gaps calling for further investigation, not as settled facts. Notwithstanding the qualifications noted above concerning the building’s own fabric, the Gunpowder Magazine’s documented function as an indispensable part of the Hospitaller function, power and legacy gives it significance of National to International importance: a contributing component of the UNESCO-inscribed Medieval City of Rhodes, protected under Greek Archaeological Law.

National

Protected under Greek Archaeological Law by Ministerial Decision ΥΑ 23084/737 (25 August 1948), ΦΕΚ 10 (23 September 1948), confirmed under Law 3028/2002 on the Protection of Antiquities and Cultural Heritage in General.

UNESCO

Medieval City of Rhodes (ref. 493), inscribed 1988, criteria (ii), (iv) and (v). A contributing component of the property as part of the wider Arsenal complex, not individually named in the Statement of Outstanding Universal Value.

References

Bevilacqua, Marco Giorgio. “The Conception of Ramparts in the Sixteenth Century: Architecture, ‘Mathematics’, and Urban Design.” Excerpt supplied as project documentation (Heritage Narrative Asset 07); cited for the general history of gunpowder and artillery technology and its effect on fortification design.
DeVries, Kelly. Guns and Men in Medieval Europe, 1200–1500: Studies in Military History and Technology. Collected Studies. Aldershot: Ashgate/Variorum, 2002.
DeVries, Kelly, and Robert D. Smith. Rhodes Besieged: A New History. Stroud: The History Press, 2011.
Hall, Bert S. Weapons and Warfare in Renaissance Europe: Gunpowder, Technology, and Tactics. Baltimore: Johns Hopkins University Press, 1997.
Hellenic Government Gazette (ΦΕΚ). Ministerial Decision 23084/737 (25 August 1948), ΦΕΚ 10 (23 September 1948), protection of the monuments of the Medieval Town of Rhodes; Law 3028/2002 on the Protection of Antiquities and Cultural Heritage in General.
ICOMOS. ICOMOS Charter for the Interpretation and Presentation of Cultural Heritage Sites. Paris: ICOMOS, 2008.
ICOMOS Australia. The Burra Charter: The Australia ICOMOS Charter for Places of Cultural Significance. Burwood: ICOMOS Australia, 2013.
Manoussou-Ntella, Katerina. “Byzantine Rhodes. The Evolution of a Fortified Harbour-city in the Eastern Mediterranean (4th to 12th c.).” In Johannes Preiser-Kapeller, Taxiarchis G. Kolias and Falko Daim, eds., Seaside of Byzantium. Harbours and Anchorages of a Byzantine Empire, Byzanz zwischen Orient und Okzident 21, 167–177. Mainz, 2021. Cited for general Byzantine-period harbour-quarter context, and for the secondary citation of Pitilakis, Sextos, Manousou-Della and Galazoula’s restoration study of the Armoury (Oplothiki) De Milly.
Papathanasiou-Zuhrt, D. RecordSheet 5.1: Arsenal of the Knights, Rhodes Mediaeval Town (Asset 14B). SEE TCP Project SAGITTARIUS, WP5 Heribuilder, Act. 5.1: The Transnational Heritage Register, Output 1: Heritage Record Sheet. Project documentation, co-financed by the European Commission (ERDF/IPA), 2011–2014. Cited for the location, coordinates, ownership and administrative history of the wider Arsenal complex, and for the Roger de Pins attribution and the Bank of Sicily claim.
Parker, Geoffrey. The Military Revolution: Military Innovation and the Rise of the West, 1500–1800. 2nd ed. Cambridge: Cambridge University Press, 1996.
Phillips, Simon D. “The Shining Virgin, Sappers and Silent Night Assaults: Comparisons with the Precursors to the 1565 Siege.” In Besieged: Malta 1565, vol. 1, edited by Maroma Camilleri, 107–116. Valletta: Malta Libraries and Heritage Malta, 2015.
Phillips, Simon David. “Rhodes in the Final Hospitaller Years, 1502–1521: Latin and Greek Interaction in the Aegean and Eastern Mediterranean.” PhD dissertation, National and Kapodistrian University of Athens, Faculty of Philosophy, Department of History and Archaeology, 2021. Directly consulted for this document; cited for its historiographical review of the 1522 siege and surrender (including Helen Nicholson’s suggestion that the treason charge against d’Amaral may reflect a personal rivalry with l’Isle-Adam, and its critique of Henry Sire’s unfootnoted claim blaming “the Greeks” for the surrender), and for its reproduction of a contemporary eyewitness account of the siege by the French knight Jacques de Bourbon (Letters and Papers of Henry VIII, 1521–1523).
Pitilakis, K., A. Sextos, K. Manousou-Della and I. Galazoula. “Η αποκατάσταση της ιππότικης Οπλοθήκης De Milly στη μεσαιωνική πόλη της Ρόδου” [The restoration of the Knights’ Armoury De Milly in the medieval town of Rhodes]. In 15 Χρόνια Έργων αποκατάστασης στη Μεσαιωνική Πόλη της Ρόδου, Πρακτικά του Διεθνούς Συνεδρίου, 160–176. Athens, 2007. Identified via secondary citation only; not directly consulted for this document (see Conservation and Management, above).
REBOOT Statement of Significance: Castellania, Rhodes (2026) — cited for consistent treatment of designation references and unresolved-scholarship presentation conventions.
REBOOT Statement of Significance: Fort of St Nicholas, Rhodes (2026) — cited for the documented link between Ottoman gunpowder bombardment in the First Siege of Rhodes (1480) and Grand Master Pierre d’Aubusson’s subsequent construction of a gun-resistant outer bastion, formally accepted in 1482.
Rocchi, E. “Le Artiglierie Italiane del Rinascimento e l’Arte del Getto.” L’Arte, pp. 347–372 (exact volume and year not stated in the excerpt supplied to this project); excerpt supplied as project upload. An Italian art-historical study of Renaissance artillery-founding; cited specifically for its identification of the Vicentine military architect Basilio della Scola as “a fortifier of Rhodes and also a skilled artillerist” who later served Charles VIII of France — a named individual corroborating the link this document draws between fortification design and artillery expertise at Rhodes. The source does not further date or detail della Scola’s work at Rhodes, and no other source reviewed for this document corroborates it.
Rogers, Clifford J., ed. The Military Revolution Debate: Readings on the Military Transformation of Early Modern Europe. Boulder, CO: Westview Press, 1995.
Setton, Kenneth M. The Papacy and the Levant (1204–1571), Vol. III: The Sixteenth Century to the Reign of Julius III. Philadelphia: American Philosophical Society, 1976. Chapter 6, “Hadrian VI, the Fall of Rhodes, and the Antiturcica of Erasmus.” Directly consulted for this document; cited for the academic account of the 1522 siege, the trial and execution of Andreas d’Amaral, and Grand Master l’Isle-Adam’s own contemporaneous letter on the reasons for the surrender.
The 1453 Ottoman siege of Constantinople, Sultan Mehmed II’s use of large-calibre bronze bombards (including the gun attributed to the Hungarian engineer Orban), and the Ottoman sieges of Hospitaller Rhodes in 1480 and 1522, are well-established general history; this material is not drawn from this project’s uploaded source materials and is cited here solely for wider military-historical context on the significance of gunpowder artillery.
Toichkin, Denis, and Manouchehr Moshtagh Khorasani. “Arms and Armour of Hospitaller Knights.” In Besieged: Malta 1565, vol. 1, edited by Maroma Camilleri, 213–222. Valletta: Malta Libraries and Heritage Malta, 2015.
UNESCO World Heritage Centre. “Medieval City of Rhodes.” World Heritage List, ref. 493. Inscribed 1988. https://whc.unesco.org/en/list/493.
Vertot, René-Aubert de. The History of the Knights Hospitallers of St. John of Jerusalem, vol. III (1757 English edition), Books VII–IX. Cited via this project’s own extensive prepared summary, “An Extensive Summary of Vertot’s The History of the Knights Hospitallers of St. John of Jerusalem, Volume III...” (prepared September 2026), covering the mastership of Pierre d’Aubusson and the Great Siege of Rhodes of 1480 through Suleiman the Magnificent’s siege and capture of Rhodes in 1522. An eighteenth-century secondary synthesis, itself following near-contemporary historians including Bosio; treated in this document as a strong narrative tradition rather than an independently verified primary source, except where corroborated by Setton’s academic account or by contemporary eyewitness testimony.