A phase, not a sudden beginning
The “new era” in this title is best understood as the Mature Harappan phase, the period of about 2600 to 1900 BCE when the Indus cities took the form that made the culture famous. It was not a break from nothing. It grew out of long-established farming villages, and it later gave way to a quieter period of smaller communities. Archaeologists divide the whole sequence into three broad stages, with dates that are approximate and vary by region:
- Early Harappan, roughly 3300 to 2600 BCE.
- Mature Harappan, roughly 2600 to 1900 BCE.
- Late Harappan, roughly 1900 to 1300 BCE, with considerable regional variation.
Some scholars use other names, such as regionalisation, integration and localisation eras, for the same broad pattern.
What came before
Farming villages existed in the northwest of the subcontinent from about 7000 BCE, as at Mehrgarh in Baluchistan. By the centuries before 2600 BCE, regional cultures with distinctive pottery were growing in the Indus plains and nearby uplands. Some towns, such as Kot Diji in Sindh, were fortified, and others, such as Kalibangan, show early town planning. Craft specialisation and long-distance exchange of stone and shell were already under way. Because these societies were separate regional traditions, the Early Harappan stage is better thought of as a set of neighbouring cultures than as one unified civilization.
The Mature phase: shared standards
What marks the Mature phase is the spread of common practices over a very large area. Several are especially useful for archaeologists.
Bricks. Baked bricks were made to consistent proportions, often given as roughly 1:2:4 for thickness, width and length. Similar bricks are found at sites hundreds of kilometres apart.
Weights. Small cubes of chert and other stones were used as weights. They follow a regular series, doubling at first (1, 2, 4, 8 and so on) and then moving to decimal-based multiples. A basic unit of about 13 to 14 grams is often suggested, though the exact figure is estimated rather than known.
Seals and script. Square steatite stamp seals with animals and signs became widespread, and the script appears across the region. Unlike the writing of the Mesopotamian civilization, it was used mostly in very short inscriptions.
Planning. Major towns had defended citadels, lower towns, drains and wells. Mohenjo-Daro’s Lower Town street grid is the best known example, though other cities such as Dholavira were laid out differently.
What the standards do and do not show
The uniformity is striking, but it does not tell us who enforced it. It could have come from a central ruler, from merchant networks, from shared customs, or from some combination. Regional differences also persisted in pottery, diet and local crafts, so “Mature Harappan” describes a shared set of traits more than a single state. The evidence for administration is mostly indirect, such as seal impressions, which suggests goods were marked or sealed.
Towns, trade and daily life
In this phase, the Indus region traded beads, shell and other goods with the Gulf and Mesopotamia, and craft workshops operated within cities. Farming settlements supported urban populations. Our knowledge of daily life comes from houses, craft debris, figurines and toys, rather than from texts, which cannot yet be read.
The shift to Late Harappan communities
From about 1900 BCE the signs of the Mature phase change. Large cities such as Mohenjo-Daro were abandoned or reduced, the script and standardised weights fade from the record, and long-distance trade of the earlier kind declines. People did not disappear. Late Harappan settlements are found in Punjab, Haryana and Gujarat, and in the upper Ganges-Yamuna region, often smaller and more rural, and the ceramics show both continuity and change. At Harappa itself the Late phase includes a cemetery with distinctive burials, once thought to belong to invaders and now generally treated as part of local developments. The reasons are debated, and most Indus decline theories stress climate, river shifts and changing trade routes rather than any single cause.
Dating the phase
The dates of 2600 to 1900 BCE come from radiocarbon dating of charcoal, bone and other materials, along with comparison to datable objects from Mesopotamia. Calibration and the choice of samples mean that the boundaries are approximate, and some sites seem to have flourished a little earlier or later than others.