Explanation:

Buranjis are a class of historical chronicles, written initially in the Ahom and afterwards in Assamese language. The first such Buranji was written on the instructions of the first Ahom king Sukaphaa who established the Ahom kingdom in 1228.
There were two kinds of Buranjis: one maintained by the state (official) and the other maintained by families.
Many such manuscripts were written by scribes under the office of the Likhakar Barua, which were based on state papers, diplomatic correspondences, judicial proceedings, etc.
Others were written by nobles or by people under their supervision, sometimes anonymously.
These documents reveal chronology of events, language, culture, society and the inner workings of the state machinery of the kingdom.