Dark Age of the Assamese language
During British India, it imposed Bengali Language over Assamese as it took over Assam.
The duration for which Bengali Language was imposed was knows as The Dark Age of Assamese Language, i.e., Bengali Language eclipsed over Assamese. This duration lasted for about 44 years, from 1832 until 1876.
Upon British took over Assam, the clerical and technical workers that they brought were Bengali who moved in to Assam. Then Bengali tried to kill Assamese language with their vested interests using British Political powers imposing Bengali as the medium of instruction in schools and colleges and for all official purposes.
Nathan Brown, an American Baptist missionary to India, was widely regarded as one among the rescuers of Assamese Language being eclipsed by Bengali, i.e., he led rescue of Assamese language from Bengali overtake.
In order to put back Assamese Language, he took the matter to that time British India administration. Eliza Brown was Nathan's wife and she had been partner of her husband's mission.