The early record of Nagas goes back to the medieval period of Indian history. Its existence was mentioned in written documents of the Ahom kingdom. The Nagas were typically isolated from the outside world besides contact with the Ahom kingdom. It all changed in the 19th century when the Burmese Empire invaded Assam allowing them to live under the Burmese rule.
Furthermore, the 1830s marks the entry of Europeans to the Naga Hills. It also leads to the abolishment of traditional practices such as headhunting and the introduction of Christianity.
Nagas also participated in World War I with over 2000 citizens enlisted in the BIA (British Indian Army). They also fought in World War II against Japanese forces to prevent them from invading the hills.
After India gained independence from British rule in 1947, Nagas became Indian citizens amid an ongoing ethnic conflict. Initially, Nagas didn’t want to be included in the Reformed scheme of India under British India. They wanted to be free of outside authority and explicitly mentioned to leave them alone and determine themselves as per their traditions.
It was the first awakening of NagaNational and after India’s independence from British rule, there was a rise of National activities among a certain group of the Nagas. It led to numerous violent incidents. Several agreements and peace talks were held with the Indian government during this period.
The year 1975 is significant in Naga history as some leaders from the largest rebel groups lay down their guns and acknowledge the Indian constitution. Some groups didn’t agree and the insurgent activity is still ongoing.
https://en.wikipedia.org/wiki/Timeline_of_Naga_history
https://en.wikipedia.org/wiki/History_of_the_Nagas