The new union brought together various states defined by ethnic identity, many of whom had centuries-long histories of autonomy from and struggles against each other. In the interest of securing their collective independence from Britain, the tribes reached an agreement to submit to collective governance -- with power sharing among the ethnicities and states -- for ten years, after which each tribe would be afforded the right to secede from the union. The terms of this "Panglong Agreement" were enshrined in the 1947/1948 constitution of the new Union of Burma. The new central government of the nation quickly worked to consolidate its power, marginalizing and angering tribal leaders and setting off more than a decade of armed conflict. In 1961, more than 200 ethnic leaders from the Shan people, Kachin people, Red Karen, Karen people, Chin peoples, Mon people and Rakhine people met with ethnic Bamar (Burmese) central government authorities to draft a new form of government which would ensure the tribes both autonomy and self-determination within a federal system.