How it began
Around 2100 BCE a group of merchants from the Indus Valley settled on the island of Dilmun, which is modern Bahrain, midway between their homeland and Mesopotamia. According to the British Museum, they brought sealing, writing conventions and standard weights with them, married into local families and took up Dilmunite traditions by about 2050 BCE. Operating out of Bahrain, they developed a new circular stamp seal carrying Indus motifs. Scholars call it the Gulf type.
Before it existed
From about 2600 to 1900 BCE the Harappan culture of the Indus Valley used square stamp seals. Each was carved with an animal in profile, such as a unicorn, a long-horned bull or an elephant, with a line of Indus script. Some of these square seals have been found in Mesopotamia and Oman. The circular shape of the Gulf type is rarely found at Indus sites and was probably adopted from Iran, where it was common at the time.
How it works
A Gulf-type seal is a small disc, mostly of steatite with a white glaze. The back has a domed handle pierced for a cord and cut with one to three parallel grooves. The face is engraved, typically with a short-horned bull, and some seals also carry an inscription. Pressed into a soft surface, it left the owner's mark. On seals from Bahrain and Mesopotamia the signs no longer match known Indus texts, which suggests the carvers had lost literacy in that script.
How it spread
Gulf-type seals are found mostly in Mesopotamia and Bahrain, and more rarely in the Indus Valley and Iran, which shows where Dilmunite merchant communities were present. One example was excavated by Leonard Woolley in a shaft grave at Ur in southern Iraq in 1931 to 1932. Differences in imagery, diameter, thickness and handle height between regions point to several local production centers. The findspots suggest that inscribed seals belonged to long-distance traders and plain ones to merchants working locally on Bahrain.
What lasted
The seals remained in use until about 1650 BCE, and from about 2050 BCE they were placed in the mound burials of Bahrain. Their wide distribution is evidence of the maritime trade network that linked Mesopotamia, the Gulf and the Indus Valley in the late third and early second millennia BCE. The British Museum describes the changes in the seals over time as a record of how Harappan and local traditions were blended.
