The early Greeks were all pirates. Minos, who had ruled the sea, was perhaps only the most successful in brigandage ; his domination was limited to the surroundings of his island. But when the Greeks became a people, the Athenians obtained the true command of the sea, because that commercial and victorious nation laid down the law to the most powerful monarch of that time,  and humbled the maritime forces of Syria, the island of Cyprus, and Phoenicia.
I must say something about this rule of the sea which Athens held. Athens, says Xenophon, “rules the sea ; but since Attica adjoins land, enemies ravage her while she is sending expeditions afar. The principals allow their lands to be destroyed, and secure their possessions on some island ; the populace, which has no lands, lives without any worry. But if the Athenians lived on an island, and in addition ruled the sea, they would have the ability to harm others without others being able to harm them, while they would be masters of the sea.”  You would think Xenophon was meaning to speak of England.
Athens, full of glorious plans ; Athens, which increased jealousy instead of increasing influence, more keen on extending its maritime rule than enjoying it ; with such a political government that the populace divided up the public revenues while the rich were being oppressed ; did not engage in the great trade promised by the work in her mines, her multitude of slaves, the number of her seamen, her authority over the Greek cities, and more than all that, Solon’s excellent institutions. Her dealing was almost limited to Greece and the Euxine Sea, from which she drew her subsistence.
Corinth separated two seas, opened and closed the Peloponnesus, and opened and closed Greece. She was a city of the greatest importance at a time when the Greek people was a world, and the Greek cities nations ; she conducted considerable trade. She had a port to receive the merchandise of Asia ; she had another to receive the merchandise of Italy : for as the Maleas promontory, where opposing winds meet and cause shipwrecks, could be rounded only with great difficulty,  they preferred to go to Corinth, and vessels could even be made to pass from one sea to the other over land. In no city were artful machines so perfected. Religion completed the corruption of what morality opulence had left. It erected a temple to Venus where more than a thousand courtesans were consecrated. From this seminary came most of the celebrated beauties whose history Athenæus dared to write. 
Four great events which occurred in Alexandria changed the face of commerce : the capture of Tyre, the conquest of Egypt, the conquest of the Indies, and the discovery of the sea which lies to the south of this country.  The Greeks of Egypt found themselves in a position to trade mightily : they were masters of the ports on the Red Sea ; Tyre, the rival of every trading nation, was no longer ; they were not impeded by the country’s ancient superstitions  ; Egypt had become the center of the universe.
The Persian empire extended as far as the Indus.  Long before Alexander, Darius  had sent navigators who descended that river and went as far as the Red Sea. Why then were the Greeks the first to trade with the Indies by a southern route ? Why had the Persians not done so earlier ? What use had they made of seas that were so close to them, even seas that washed their empire ? It is true that Alexander conquered the Indies, but must one conquor a country in order to trade there ? I shall examine this question.
Ariana, which extended from the Persian Gulf to the Indus, and from the southern sea to the mountains of the Paropamisadæ, was indeed dependent in a sense on the Persian empire ; but in its southern part it was arid, parched, uncultivated and wild.  Tradition had it that the armies of Semiramis and of Cyrus had perished in these wildernesses ; and Alexander, who had his fleet follow him, did not fail to lose a large part of his army there  The Persians were leaving the entire coast in the power of the Icthyophagi,  the Oreitæ and other barbarian peoples. Moreover, the Persians were not great navigators, and their very religion obviated any thought of maritime trade.  The navigation that Darius sent to the Indus and the Indian Sea was more the fantasy of a prince who wants to display his might than the orderly plan of a monarch who wants to use it. It went no farther, either for commerce or for the marine, and they emerged from ignorance only to plunge back into it.
Moreover, it was commonly thought  before Alexander’s expedition that the southern part of the Indies was uninhabitable,  which followed from the tradition that Semiramis  had brought back only twenty men from there, and Cyrus only seven.
Alexander entered from the north. His plan was to march to the east ; but after finding the southern part filled with great nations, cities, and rivers, he attempted its conquest, and succeeded.
At that point he conceived the plan of uniting the Indies with the west through a maritime trade, as he had united them by means of the colonies he had established inland.
He had a fleet constructed on the Hydaspes, descended that river, entered the Indus, and navigated to its mouth. The fleet followed the coast from the Indus along the shore of the lands of the Oreitæ, the Icthyophagi, of Caramania, and of Persia. He had cities built ; he forbade the Icthyopagi to live on fish : he wanted the shores of that sea to be inhabited by civilized nations. Onesicritus and Nearchus kept a journal of this voyage, which took ten months. They reached Susa ; there they found Alexander, who was feasting his army ; he had left his fleet in Patala  to continue overland.
The conqueror had founded Alexandria for the purposes of securing Egypt ; it was a key to open it in the very place  where the kings his predecessors had a key for closing it ; and had no thought about any commerce, which the discovery of the Indian sea alone could have suggested to him. 
The kings of Syria left the southern Indian trade to those kings of Egypt, and adhered only to the northern trade which was plied via the Oxus and the Caspian Sea. It was believed in those times that this sea was part of the Northern Ocean.  Seleucus and Antiochus made a special point of exploring it. They maintained fleets there.  What Seleucus explored was called sea of Seleucus ; what Antiochus discovered received the name of sea of Antiochus. Alert to projects they might have in that region, in hopes of taking Europe from the rear through Gaul and Germania, they neglected the southern seas, either because the Ptolemys with their fleets on the Red Sea had already claimed them for themselves, or because they had discovered that the Persians were invincibly uninterested in the marine, or finally because the general submission of all the peoples in that region left them no more hope for conquest.
I confess I cannot understand the obstinacy of the Ancients in believing that the Caspian Sea was part of the ocean. The expeditions of Alexander, of the kings of Syria, of the Parthians and the Romans, could not make them change their thinking ; and yet they describe the Caspian Sea for us with admirable precision, which is because we correct our errors as slowly as we can. At first they knew only the south of the Caspian Sea, and they took it to be the ocean ; as they progressed along its shores on the northern side, instead of imagining a great lake, they again thought it was an ocean inlet ; when they explored the northern coast and had almost completed the circle, their eyes were open, but they closed : they took the mouths of the Volga for a strait or an extension of the ocean.
Alexander’s land army had gone on the eastern side only as far as the Hyphasis, which is the last of the rivers that flow into the Indus. Thus the first commerce the Greeks had in the Indies took place in a very small part of the country. Seleucus Nicator continued as far as the Ganges  : and so was discovered the sea to which that river flows, which is the Gulf of Bengal. Today we discover lands by sea voyages ; there was a time when they discovered seas by conquests of land.
Strabo, despite the testimony of Apollodorus, seems to doubt that the Greek kings of Bactriana  had gone farther than Seleucus and Alexander.  I do believe they went no farther to the east, and did not cross the Ganges ; but they went farther southwards, and discovered Siger and ports of Malabar, which gave rise to the navigation I am about to discuss.
Pliny tells us that they took three routes successively to sail to the Indies.  First they went from the Siagre promontory to the island of Patala, which is in the mouth of the Indus ; it is clear that this is the route which Alexander’s fleet had followed. Next they took a shorter and surer route, and went from the same promontory to Siger.  This Siger can only be the kingdom of Siger mentioned by Strabo, which the Greek kings of Bactriana discovered.  Pliny can only say that this route was shorter because they covered it in less time ; for Siger must have been further away than the Indus, since the kings of Bactriana discovered it. They must in that way have avoided detouring around certain coasts, and taken advantage of certain winds. Finally, merchants took a third route : they went to Cane or to Cella, ports on the mouth of the Red Sea, from where, with a westerly wind, they reached Muziris, the first stop in the Indies, and from there other ports.
We see that instead of going from the mouth of the Red Sea to Siagre by going up the coast of Arabia Felix to the northeast, they went directly from west to east, from one side to the other, thanks to the trade winds, whose regular pattern was discovered by sailing in this vicinity. The Ancients went off the coasts only when they used these winds, which were a sort of compass to them.
Pliny says that they left for the Indies in the middle of summer and returned towards the end of December or at the beginning of January.  That is entirely consistent with the journals of our navigators. In that part of the Indian Sea which is between the African peninsula and the peninsula this side of the Ganges, there are two monsoons : the first, during which the winds blow from west to east, begins in August and September, and the second, during which the winds blow from east to west, begins in January. Thus we leave Africa for Malabar at the time Ptolemy’s fleets departed, and we return at the same time.
Alexander’s fleet took seven months to go from Patala to Suza. It left in July, in other words during a season when today no ship dares take to sea, to return from the Indies. Between one monsoon and the other, there is an interval of time during which the winds vary, and when a northerly wind joining with ordinary winds causes dreadful storms, especially near the coasts. That lasts for the months of June, July, and August. Alexander’s fleet, leaving Patala in July, must have weathered many storms ; and the voyage must have been long, because they were sailing against the monsoon.
Pliny says that they left for the Indies at the end of summer : thus they were using the time when the monsoon was shifting to cross from Alexandria to the Red Sea.
Do note how much better we progressively became at navigation. The voyage of Darius to descend the Indus and reach the Red Sea lasted two and a half years.  Alexander’s fleet, descending the Indus, reached Suza ten months later, having navigated three months on the Indus and seven on the Indian Sea  ; subsequently the voyage from the Malabar Coast to the Red Sea was covered in forty days. 
Strabo, who explains their ignorance of the countries that lie between Hyphasis and the Ganges, says that among the navigators who go from Egypt to the Indies there are few who go as far as the Ganges.  Indeed we see that the fleets did not go there : they followed the trade winds from west to east from the mouth of the Red Sea to the Malabar coast. They put into what ports there were, and did not try to sail around the peninsula this side of the Ganges by Cape Comorin and the coast of Coromandel ; the navigation plan of the kings of Egypt and of the Romans was to return the same year. 
Thus it is far from the case that the commerce of the Greeks and Romans to the Indies was as extensive as ours, we who know vast countries which they did not know, we who do our trading with all the Indian nations, and even trade and ship for them.
But they plied this trade with greater ease than we do ; and if today we traded only on the coast of Gujarat and Malabar, and if without going to seek the southern islands we contented ourselves with the merchandise which the islanders might bring to us, going by way of Egypt ought to be preferred to going by way of the Cape of Good Hope. Strabo says that is the way they traded with the peoples of Taprobana. 
I shall end this chapter with an observation. Ptolemy the geographer  extends the known eastern Africa to the Prassum promontory, and Arrian limits it to the Raptum promontory.  Our best maps place the Prassum promontory in Mozambique around ten degrees of that latitude. But since, from the coast of the kingdom of Azania, which produces no merchandise at all, the country becomes ever richer as one goes south to the land of Sofala, where lies the source of wealth, it at once seems surprising that we have thus retrogressed toward the north instead of advancing toward the south.
As discovery, navigation and commerce extended in the direction of the Indies, they receded on the African side : a rich and easy trade led people to neglect a less lucrative one full of difficulties. The eastern coast of Africa was less known than in the time of Solomon ; and although Ptolemy speaks of the Prassum promontory, it was rather a place that had been known than a place that was still known. Arrian bounds known lands at the Raptum promontory because no one went that far any more.  For if Marcian of Heraclea  returned to the Prassum promontory, his authority is of no importance : he himself admits that he is copying Artemidorus and that this Artemidorus is copying Ptolemy.