IG II2 1128 (=Rhodes-Osborne GHI 40) poses a long-standing riddle. This fourth-century BC Athenian inscription records parts of decrees passed by three Kean poleis requiring that these communities export μίλτος (ruddle or red ochre) exclusively to Athens and in designated ships. Penalties and enforcement mechanisms are severe. Ancient sources suggest that Kean μίλτος was of unusually high quality (Theophr. De lapidibus 52), a fact confirmed by modern investigation (Photos-Jones et al. 1997). Relying on scattered literary references to ships painted with μίλτος, Hasebroek (1933: 141) and a host of subsequent scholars argued that Athens’ interest in Kean μίλτος reflected its importance in naval applications. That theory has recently been discredited (Osborne 2000; Lawrence 2004; Rhodes-Osborne GHI 40). Although Herodotus suggests that there was once a time when all ships were painted with μίλτος (3.58), it is pitch that made ancient wooden hulls watertight and there is no evidence to suggest that μίλτος served any necessary function in preserving the hulls of Athenian triremes. From that point of view Athens’ actions cannot but seem capricious and “extremely high-handed” (Rhodes-Osborne, p. 209), an interpretation that in turn holds important implications for our understanding of the nature of Athens' renewed maritime confederation.
I argue that while Kean μίλτος may in actual fact have served no necessary strategic purpose the Athenians nevertheless believed that it played a vital role in the maintenance of their fleet and this belief ultimately had its origins in the relatively timeless practices of Greek agriculture. Crucial evidence suggests that Greek farmers attempted to protect against woodboring larvae (σκÏŽληκες and θρίπες) by applying μίλτος —sometimes mixed specifically with pitch—to the roots or trunks of vines and trees. Admittedly much of this evidence is preserved only in the Geoponika, a Byzantine farming manual. But this underutilized anthology incorporates material from a wide range of ancient sources (Decker 2009: 263-271; Dalby 2011: 9-14). Pertinent evidence is attested in passages attributed to no fewer than four different agricultural writers—Leontinos (10.50), Paxamos (13.10), Didymos (10.45) and Florentinus (10.90), while additional evidence can be gleaned from a range of authors both Greek and Latin, suggesting a traditional Greek (or wider Mediterranean) agricultural practice.
The nexus between agricultural and maritime practice is the τερηδÏŽν, or shipworm, “the principal enemy of wooden-hulled ships in Mediterranean waters” (Morrison, Coates and Rankov 2000: 186). Although the shipworm is actually a marine mollusk, Greek and Latin sources suggest that marine and terrestrial woodborers were commonly associated. Theophrastus discusses shipworms together with σκÏŽληκες and θρίπες (Historia plantarum 5.4.4-5), while a range of medical and other texts use τερηδÏŽν not to describe shipworm but various terrestrial larvae and parasitic worms. Latin authors such as Columella likewise use teredo in agricultural contexts as a term for terrestrial woodborers (De re rustica 4.24.6).
The implication is clear: the archaic Greek farmers whom Hesiod imagines trading their agricultural surpluses by sea (WD 641-694) would have applied to the problem of ship maintenance whatever limited experience they had available. In the case of shipworm that traditional knowledge proved largely ineffectual and by the fourth century BC Greek merchant ships were regularly sheathed in lead (Casson 1986: 214-6). But that option was unavailable for triremes, which relied on dry, light hulls for speed and maneuverability. For these triremes shipworm posed an inexorable threat, a fact well known to the audience of Aristophanes, one of whose triremes in Knights imagines herself being “devoured by shipworms” (ὑπὸ τερηδÏŒνων σαπεá¿–σ’, 1308). Indeed estimates suggest that a modest infestation would have increased by at least a factor of nine the rate at which ancient triremes became waterlogged (Steinmayer and Turfa 1996). In the fourth century, memory of the Sicilian disaster—precipitated in part by the crippling effects of a waterlogged fleet (Thuc. 7.12)—offered a vivid lesson. For some Athenians interested in maintaining a renewed maritime confederation their monopoly on the very best μίλτος from Keos still seemed of vital strategic importance.