Sindh was home to one of the world's oldest civilizations, the
Indus Valley civilization from which Indian civilization emerges,it is there lot before the birth of Islam.It was ruled by Rai dynasty before caliph Ummars capture of Sindh.
In response of Caliph Umar's question about the Makran region, the messenger from Makran answered:
'O Commander of the faithful!
It's a land where the plains are stony;
Where water is scanty;
Where the fruits are unsavory;
Where men are known for treachery;
Where plenty is unknown;
Where virtue is held of little account;
And where evil is dominant;
A large army is less for there;
And a less army is use-less there;
The land beyond it, is even worst. [referring to Sind]
Listening this Caliph stopped marching for further and not crossed Indus river.