Coins as Evidence of Conflict: How Roman Hoards and Epigraphy Map Ancient Piracy in the Arabian Sea

The ancient trade routes across the Arabian Sea are often romanticized as smooth conduits of silk, pepper, and gold. Primary textual records and physical artifacts show a far more brutal environment. Mediterranean merchant vessels navigating the monsoon winds were forced to contend with maritime violence, privateering, and organized piracy along the western littoral of India.

Physical evidence of these disruptions survives in two distinct formats: the numismatic record of defaced Roman hoards buried along the Malabar Coast and inland trade routes, and Tamil-Brahmi kalvettu (stone inscriptions) detailing local defense networks. Together with classical texts, these artifacts map how ancient maritime networks adapted to state-sanctioned and autonomous sea raiding.

Written Warnings: Nitrias and Maritime Hazards

The most direct literary account of ancient piracy in the region appears in the Periplus Maris Erythraei (Periplus of the Erythraean Sea), an anonymous first-century CE Greek navigational guide. Section 53 of the text warns navigators approaching the Malabar Coast about the port of Muziris.

⚖ Scholarly debate surrounds the exact geographic location of ancient Muziris. Evidence shows that two major archaeological sites in Kerala—Pattanam and Kodungallur—are the primary candidates among scholars, though no definitive epigraphic proof has exclusively settled the identification.

The author of the Periplus notes that shipping near Muziris was vulnerable due to pirates operating out of a nearby stronghold called Nitrias. Roman natural historian Pliny the Elder echoes this warning in his Naturalis Historia (Natural History). Pliny observes that merchants traveling to Indian emporia had to carry companies of archers aboard their vessels because the seas were infested with pirates. He specifically names Nitrias as a center of pirate activity, noting that ships anchored far from shore to avoid sudden amphibious raids.

Scholars debate the exact geographic identity of Nitrias, though consensus places it near the mouth of the Netravati River near modern Mangalore or along the estuaries of coastal Karnataka. Evidence shows these coastal inlets provided ideal cover for light, fast craft to strike heavy Roman merchantmen (gauloi, round-hulled cargo ships) laden with coin and bullion.

Defaced Denarii and Slashed Aurei

The violence recorded in texts leaves a physical mark on the numismatic record. Tens of thousands of Roman silver denarii (standard Roman silver coins) and gold aurei (standard Roman gold coins) have been recovered from hoards across South India, particularly along the Palghat Gap—a natural mountain pass connecting Kerala to Tamil Nadu.

A significant portion of these coins bears deliberate physical modifications. Hoards unearthed at sites such as Iyyal in Kerala and Pudukkottai in Tamil Nadu contain Roman coins marked by deep chisel cuts or slashes across the obverse side. In almost every instance, these cuts target the imperial portrait, defacing the bust of emperors such as Augustus, Tiberius, or Claudius.

Numismatists debate the precise function of these slash marks. One perspective holds that local authorities or shresthins (trade guild leaders or moneyers) slashed the coins to test metal purity, ensuring the coin was not a plated copper core (subaeratus, a base-metal core coated with precious metal). Another perspective argues that the slash served as a formal demonetization mark. By defacing the portrait of the foreign sovereign, local rulers invalidated the Roman coin's political authority while validating its value strictly as bullion within indigenous exchange networks.

In the context of maritime piracy, these modified hoards tell a broader story. Large hoards of slashed silver denarii buried together in remote inland transit points indicate emergency concealment. Merchants and inland chieftains buried their liquid wealth when coastal raids or transit ambushes threatened inland supply lines.

Epigraphic Defenses: Tamil-Brahmi and Regional Mandates

While Roman coins document the economic scale and risks of the trade, Tamil-Brahmi epigraphy provides insight into local state responses. Sangam-era inscriptions carved into rock shelters and stone slabs record how local dynastic powers—primarily the Cheras, Cholas, and Pandyas—managed maritime security.

Port inscriptions and naadukal (hero stones raised for fallen warriors) document the deployment of armed guards to secure littoral zones. Tamil-Brahmi epigraphs from coastal hubs detail taxes levied on trade to fund port garrisons and littoral patrols. Early Tamil literature—such as the Akananuru and Purananuru—complements these epigraphic records by describing Chera naval vessels patrolling the mouths of rivers to protect foreign merchant ships (yavanas, Mediterranean traders) bringing gold to exchange for black pepper.

The epigraphic corpus demonstrates that piracy was not merely an external threat to Roman ships; it was a structural challenge to South Indian states that relied on ulgu (custom duties) levied at port entry points. When raiders operating from estuaries like Nitrias disrupted ship movements, royal authorities launched retaliatory naval strikes to clear the sea lanes.

Interpreting the Numismatic and Epigraphic Record

Reconstructing ancient maritime violence requires distinguishing verified archaeological data from later historical assumptions. Physical evidence shows that Roman coinage entered the Indian peninsula in immense volume during the first two centuries CE. Physical evidence also confirms that hundreds of these coins were systematically slashed, deformed, or punch-marked before burial.

Scholarship continues to debate whether the high concentration of slashed hoards along specific river corridors reflects direct pirate activity, local political instability, or routine bullion processing by trade guilds. What the combined numismatic, epigraphic, and literary record demonstrates is that ancient Indian Ocean trade was not a passive exchange. It was an active, heavily militarized commercial system where high profits were balanced against constant maritime risk.