What was the history of national unity in Nepal

Uniting all the different cast, region , religion, language and culture group people to achieve the national goal is national unity . National unity is necessary for every nation for its overall development . But the situation of Nepal at present is some what different . People are diversifying according to their caste , region,religion , language and culture.
Historically Nepal was united . Every people were first Nepal and then of their sectors and sub sectors.Their first Goal used to be the nation benefit . The people of Himal, Hill and Terai did have very less pride of their region in front of Nepal. Likewise different caste and religion people would also ahead for national goal.
But Nepal at present is dividing in various sectors. People are more selfish toward their sectors and sub sectors forgetting Nepal as a whole e.g. People of terai are fighting against the people of hill . Similarly people of one caste are fighting against other caste.

There is of course strength in unity .But Nepalese are forgetting this because of their belief in cunning political leaders . we , Nepalese , should search for unity in diversity . If all groups of people are united for national goal , Nepal will surely be developed within few years.