But over the millennia - that has been the exception rather than the rule, in fact the present day borders of india and Pakistan have been the de facto border of the Indus and Ganges based civilizations.
No, it was only starting in the 18th century, with the collapse of the Mughal Empire and central authority, that a cultural drift between the people of the Indus and the Ganges emerged. The Durranis and tribal factions in AfPak region took advantage of the Mughal decline to exert their influence over present-day Pakistan, and the long-term effects of this power struggle are still felt today.
However, before that time the Indus and Ganges shared much the same civilization. You could call this civilization anything you want, but most historians call it as
dharmic civilization because of the ideals of
dharma, which were represented in three main religions: Hinduism, Buddhism, and Jainism.
Starting with Chandragupta in the 4th century B.C.E., most Indian empires had their
base in the Ganges and their
borders on the Indus/Afghanistan.
A few examples:
Maurya Empire, 320-185 B.C.E.
Base of power is
Pataliputra, in the Ganges. Boundaries extended to
Afghanistan.
Gupta Empire, 320-600 C.E.
Base of power is
Pataliputra, on the Ganges. Boundaries extended to the
Indus.
Pala Empire, 750 C.E. - 900 C.E.
Base of power is
Pataliputra, on the Ganges. Boundaries extended to
Afghanistan.
Delhi Sultanate, 1200-1500 C.E.
Base of power is
Delhi, on the Gangetic Plain. Boundaries extended to the
Indus.
Mughal Empire, 1526-1800s C.E.
Base of power is
Agra, on the Gangetic Plain. Boundaries extended to
Afghanistan.
Do you see a pattern here?
The Indus Valley, for most of its history, has been within the cultural, economic, and sociopolitical orbit of Ganges-based states.
