I know about Alaol and his works. He started only in 1600.
Oldest work of bengali literature was Charyapas between 8th and 12th CE.
Then Srikrishna Kirtan by Boru chandidas around 1350.
These have very little resemblance to modern Bengali.
Later came the pathbreaking work of Chandidas around 1450. He was a humanitarian poet and wrote "Shobar upor manush shotto tahar upore nai" ("Above all is humanity, none else").
Odia language inscription was found as early as 9th century AD. It is considered as a classical language, but Bengali is not.Survived in spoken form among the common folks, common sense!
Actually they did ban the language, particularly the Sena Dynasty. Buddhist monks, who were the pioneers in developing proto-Bengali through the Charyapad texts, were persecuted brutally by the Senas. Bengal became heavily Brahminized through the introduction of caste system and enforcement of Sanskrit while suppressing the Pali language which was the basis of Bengali. This is one of the major reasons why the growth of Bengali was delayed by few centuries compared to Odia language although both had the same origin.
It was only during the Sultani period that Bengali was revived. OTOH, the Charyapada texts were later discovered in early 20th century from Nepal's royal library!
He's an Indian. Gotta be patient with people requiring special needs.