Story !!!

Legend 1

Kashmir has never been an integral part of India : Arundhati Roy

The Story is :

In 1947, at the time of Indian independence, there were some princely states Hyderabad, Gwalior, Mysore, Baroda and Kashmir. They were called princely states a quasi-sovereign states ruled by the Indian Princes under the sovereignty of the British. There were as many as 568 states in India when the British decided to leave India.

Under the Mountbatten Plan for India's freedom, those princely states were given two options either affiliate with India or with Pakistan, that option was closed at the insistence of Congress party. Most of the princely states were eager for freedom. The choice of which entity to join was left to the rulers of the princely states. It was mostly understood that the religious denomination of the majority of the citizens and geographical contiguities of the states would be the preponderant settled on criteria. 

Kashmir fulfilled both these major criteria to join Pakistan geographicaly contiguity with newly formed state and religious leading of the majority of its citizens. (Though I never favor).