Ancient Sicily is the boundary mark between the eastern and central Mediterranean. This boundary is not, however, a meteorological one, for, all round Sicily, winds generally blow from the west, becoming more and more regular during the sailing season, and blowing from west to northwest or even north between Sicily and Crete, from spring to late August. The real meteorological frontiers are in fact Sardinia and the Balearic archipelagos. Nevertheless, Sicily determines two straits: the strait of Messina and the Channel between Africa and Sicily, the latter being itself divided into 3 channels:
• Malta Channel, north of a line drawn between Malta and Pantelleria,
• Sicily Channel, between Pantelleria and Sicily
• Pantelleria Channel between Pantelleria and Cape Bon
The strait of Messina is a very complex zone (Flesca 2002): violent, sudden and turbulent winds, along with strong, alternate tidal streams, whose directions change every six hours, make it not only a very complex and dangerous zone, but also an area whose crossing may need several stops in order to wait for better conditions. The myth of Charybdis and Scylla reminds us the fears it inspired. In fact, journeys bound both southwards and northward along the strait could hardly be sailed in a straight line, given the capricious character of winds and the change of direction of tidal streams. It could take several days to go from the so-called “Adriatic” (the sea south Messina) to the Tyrrhenian basin and vice-versa. Several calls were necessary, as shown by the end of Paul’s travel when the Apostle sailed, not on a small coaster, but on a grain-ship from Alexandria, which had wintered at Malta. Having left Malta it stopped first at Syracuse, then at Rhegium, before entering the Tyrrhenian, proceeding straight to Puteoli. Travelers often preferred to go by land between Syracuse and some port on the northern shores of Sicily. So did Apollonius of Tyana (Philostr. VA, V. 11; VIII. 15).
Though situated almost 40 nm east the direct line between Cape Bon and Cape Lilibeo, Pantelleria divides the Channel between Cape Bon and Cape Feto in two almost equal parts. In the main, this channel has the same orientation as the northwest prevailing winds, generating a reasonable current of half a knot to one knot, running eastwards, and getting stronger in Malta’s channel. This undoubtedly made the direct route fast and easy for ships sailing eastwards, but longer and more difficult for those sailing in the opposite direction, especially for ancient sailing ships. This was also true for oared vessels, whose ability for tacking was scarce. One can imagine how difficult a westward journey must have been when a ship whose speed, under good conditions could hardly reach 3 knots, had to face a 1 kn. current from the opposite direction. This plight is especially accentuated when one considers that the best angle one could achieve was about 60° from the wind (and actually much less given the drift). Furthermore, the square sail, even when transformed into a triangular one, made tacking a long and fastidious operation as the ship had to wear. The best solution would have been to sail southwards in order to reach the sheltered zones between Lesser Syrtis and Cape Bon, characterized by smooth summer sea-breezes blowing from the East.
Subjective geography and sea-routes
The way ancient writers used to describe those islands or how they inserted them in a series of sea-measurements gives a clear idea of some changes in their place in sea-routes, and in political sea-power. Islands, even those considered by ancient writers as “pelagic” ones (i.e. . those situated one day far or more from the mainland), such as Pantelleria, Malta and Gozo, were generally described apart from the mainland. However, after a certain stretch of land islands were supposed to fit with. The way they are described thus shows the subjective perception of their links with continents. Pantelleria, Malta, Gozo and Lampedusa are described by ps.-Skylax (111) with regard to Cape Bon, which is quite surprising as far as Malta, Gozo and Lampedusa are concerned, but is quite normal to who considers them as Punic islands, as ps.-Skylax did in the IVth century.
Diodorus Siculus (V. 12) chose to associate not only Malta and Gozo, but also Kerhennah, with Sicily, instead of Africa. This point of view is clearly an Italic one, and reflects the fall of these islands into Roman hands. On the other hand, Strabo, who uses at least three different sources, mentions the islands alternately as part of Sicily - the latter being considered as part of Italy (VI.2.11) -, or Africa (XVII.3.16). Later authors, writing after the Roman conquest, when these islands were made part of prouincia Sicilia, described them entirely with Sicily. In his overview of the Mediterranean, Strabo names Pantelleria, together with Aegimuros, as one of the islands “in front of Sicily and Libya” (II.5.19, C 123), but omits Malta, which found no place with respect to another land or the division of seas inherited from Eratosthenes. It seems that, by later times, Malta had no substantial existence in the Greek framework of the Mediterranean. According to Mela (II.7.120) and Pliny (III. 92), depending on the same lost unknown author, Gaulos, Melita and Cossura were circa Siciliam, but Africam uersus or in Africam uersae thus closer to Sicily, but on the way to Africa. Orosius (IV.8.5) names Lipara and Melita as insulae Siciliae nobiles. Some scholars (Silbermann) consider that according to Mela (II.7.120), Pliny (III.92), and Martianus Capella (VI. 648), all three islands were parts of the fretum Siculum. This is clearly true of Martianus Capella, but he probably misunderstood Mela, Pliny and their common source. According to Procopius (BV 1.14) Gaulus and Melita “marked the boundary between the Adriatic and Tuscan Seas”. For classical writers down to Pliny, “Adriatic” meant the whole sea between Peloponnesus and Sicily. The Maltese Archipelago had later reached the status of boundary-marker between the central Mediterranean system, and the west-Italian one, which then included Sicily.
Subjective geography thus shows that bridging one island with one continent or another relied much upon geopolitical considerations rather than upon Natural Landscape. It also reflects the reality of sea-routes. Pantelleria is almost always situated in respect of both Cape Bon or Kelybia (Aspis/ Clupea) and Lilybaeum.
Malta and Gozo were not considered by ancient writers as part of an archipelago. This is by no mean surprising: the same situation may be observed on other neighbouring city-islands such as Rhenea and Delos in the Cyclades. It is however of major interest to note that they belonged to a group of islands including Pantelleria, Gozo, Malta, Lampedusa and Kerkennah. In Silius Italicus, Malta appears before Cossyra, whose name, in contrast, occurs together with Gozo’s (XI. 272-274). A natural link between Pantelleria and Malta is also suggested by the naming of Malta immediately after Cossyrus, as situated further East away from Cape Bon, and by Strabo’s measurement (XVII.3.16) there was a very short distance between the two islands, that of 500 stadia. Editors have generally considered that the number is erroneous (it was probably closer to 1,500, equal to two days and one night at sea). This mistake may be traced to Strabo’s source, who considered, like Silius Italicus, that Pantelleria and the Maltese archipelago were close together. In turn this perception was probably due to the speed of the eastward route between the two points.
On the contrary, the three Islands mentioned by Diodorus (Malta, Gozo and Kerkennah) mark the westwards sea-route between Sicily and Africa through the so-called isole Pelagie. This is the exact route followed by Belisarius’ fleet (Procop., BV 1.14), from Syracuse to Malta and Gozo, and thence, after a one day sail, on to Caput-Vada (Ras Kapudia), about 75° from the prevailing winds. Thence, ships sailing to Carthage had to follow the coastline and make for Cape Bon. This explains why Agathocles’ fleet needed 6 days (DS XX.6.3) (after leaving from Syracuse) before sighting Africa and landing, maybe at Cape Bon (Casson 1971: 295, n.108), but possibly at any other point along the eastern shores of modern Tunisia. It was already familiar to an Athenian such as Thucydides, who was able to estimate its normal duration. The abnormally high freight-rate from Carthage to Sicily in the Diocletian’s Prices Edict probably refers to the same route and to the same direction (Arnaud 2007), and shows that it was probably the normal route westwards (fig. 1).
A journey from Syracuse to Carthage may thus have lasted more than thrice the normal duration of the same journey in the reverse direction. The coasting part of the same route was probably followed by the Peloponnesian, sent off in the spring from Peloponnese in the merchantman, who arrived from Neapolis, in Libya, at Selinus in August. Thucydides considered Neapolis (= Nabeul) as “the nearest point to Sicily, which is only two days' and a night's voyage” to Selinus (Thc., VII.50.2). Pantelleria was just in the middle of this route and visible from Nabeul. Although Aspis/Clupea is geographically closer to Sicily, Neapolis is actually closer for a ship sailing from Lesser Syrtis.
By the mid-4th century, when Pantelleria was reaching a noteworthy place in trade-routes, as shown by the importance of the so-called “Pantellerian ware” ceramics (Massa 2002), the Expositio totius mundi et gentium lists Sicily (66), Cossora (67) and Sardinia (68), suggesting that they were part of a same route, maybe in a broader context characterised by the increasing importance of coasting, making Pantelleria a convenient relay.
It is thus clear that the islands organized, at least as landmarks, and possibly as commercial calls, relays or destinations, were the major sea-routes round Sicily. The unusual importance of Marettimo in the maritime itinerary within the Itinerarium Antonini as compared with Pantelleria suggests that it reflects the “direct” route between Carthage and Pozzuoli/Rome (Arnaud 2004).
It is otherwise noteworthy that, according to the Ancients, as early as Dicaearch, Rhodes, the southernmost capes of Peloponnesus, the Strait of Messina (fretum Siculum or, in Greek, simply “Porthmos”, “the Strait” par excellence), South of Sardinia, the Pillars of Herakles and Gades were distributed along the same parallel. The shape of Sicily was supposed to be roughly that of an equilateral triangle whose horizontal base was made of the shores between Cape Lilybaeum and Cape Pachynum, so that, for the Ancients, the shortest way from East to West did not run through the Sicily-Malta Channel, but through the Strait of Messina. This misconception is a direct consequence of the opinion held by the Greeks that the Straits of Messina provided a more convenient sailing route (fig. 2-3).
Changes in subjective geography indicate changes in perception of the importance of islands which reflect actual changes of their role and integration in maritime trade-routes: the emergence of Malta and Gozo as the boundary-mark between two systems, is probably the clearest sign of such changes that was impacted by Roman domination (Arnaud 2004).
 “And setting sail quickly they touched at the islands of Gaulus and Melita, which mark the boundary between the Adriatic and Tuscan Seas. There a strong east wind arose for them, and on the following day it carried the ships to the point of Libya, at the place which the Romans call in their own tongue "Shoal's Head." For its name is "Caputvada," and it is five days' journey from Carthage for an unencumbered traveller”.