Evidence from two directions
The Harappans left no readable account of their trade, so the case for overseas contact comes from two kinds of evidence that support each other. One is texts from Mesopotamia, which name a distant land called Meluhha. The other is objects: Indus seals, weights and beads found far from their homeland, and Mesopotamian or Gulf goods found in the Indus region. Most scholars identify Meluhha with the Indus civilization or its region, although this is an inference from the combined evidence rather than a statement the Indus people made.
What the Mesopotamian texts say
Cuneiform texts from the later third millennium BCE list Meluhha together with two other lands, Dilmun and Magan. Dilmun is generally identified with Bahrain and nearby areas, and Magan with Oman and the region around it. Meluhha was the furthest of the three.
A text of Sargon of Akkad, who ruled around the 24th and 23rd centuries BCE, boasts that ships from Meluhha, Magan and Dilmun were moored at his capital. Later, the ruler Gudea of Lagash recorded receiving goods from distant lands, with gold dust and carnelian ascribed to Meluhha. An Akkadian-period cylinder seal belongs to a man described as a translator of the Meluhha language, which suggests that people from Meluhha, or those who spoke their language, were present in Mesopotamia, at least for a time. The texts also mention Meluhhan goods such as carnelian, ivory, wood and exotic animals, though what each term meant is sometimes uncertain.
After about 1900 BCE the references fade. In much later Assyrian texts, the name Meluhha seems to be applied to places in northeastern Africa, a reminder that place names could shift over time and that the text evidence is not always straightforward.
What the objects show
Stamp seals made in Indus style, with the typical animals and signs, have been found at sites in Mesopotamia, including the city of Ur and the old city of Susa, and in the Gulf, at places such as Failaka and Bahrain. Etched carnelian beads of types common in the Indus have also been found in Mesopotamia. Examples have been recovered from burials in Ur dated to the middle of the third millennium BCE, which is a useful anchor for the Indus chronology.
Evidence also runs the other way. Weights that follow Indus standards have turned up in Gulf sites, and Gulf-style seals have been found in the Indus region. In this setting, the Indus weights are interesting because they suggest merchants who shared a system for trading across distance, but the evidence is thin, and the volume of trade is hard to measure.
Beads and raw materials
Carnelian from Gujarat and nearby sources was a major export, as were long barrel-shaped beads made with great skill. Lapis lazuli, which was valued in Mesopotamia, probably reached the Indus via sites such as Shortugai in northern Afghanistan. Other likely goods include shell, ivory, timber and cotton textiles, though textiles rarely survive. In return, the Indus received copper and perhaps other metals from the Gulf and Oman, although local sources in Rajasthan were also exploited, so copper imports are debated.
Lothal and the ports
Lothal, near the Gulf of Khambhat in Gujarat, was an important craft centre with bead-making workshops. Its excavators identified a large brick-lined basin as a tidal dock, which for some years was cited as evidence of a Harappan harbour. Other researchers have argued that it may have been an irrigation reservoir or water tank, and the debate continues. Even without a dock, the site’s location near the coast, its seal impressions and its workshops fit a role in trade. Other coastal settlements, such as Sutkagen-dor on the Makran coast, are likewise associated with sea contact.
Sea travel along the coast to the Gulf was a practical route, and the study of ancient seafaring suggests that coastal sailing was common long before open-sea crossings. Representations of boats on seals and tablets give some idea of Harappan vessels, but not enough to reconstruct them fully.
A fresh look at the scale
Earlier accounts sometimes treated Meluhha trade as a major engine of Indus prosperity. A more cautious view is now common. The imported items found in the Indus region are few compared with the many local goods, and much trade was probably within the subcontinent and with neighbouring regions such as Afghanistan and Central Asia. Overseas exchange was real and valuable, but it was probably only one part of a larger economy. A loose parallel is Egypt’s Punt expeditions, which brought back a limited range of luxury goods by sea without implying political control.
Trade also does not mean political contact. There is no evidence of colonies, armies or rulers shared by the Indus and Mesopotamia. The exchange appears to have been commercial and cultural, carried by merchants and intermediaries, with the Gulf islands and coastal peoples playing a key role.
Why it matters
Trade ties help to date the Indus cities through Mesopotamian chronology, and they show that these cities were part of a wide world of contacts. They also raise questions that remain open: how much was carried by Indus ships, who handled the exchange in the Gulf, and why such links appear to decline after about 1900 BCE.