Tagore 's collected 1939 Bangla-language writings ( RabÄ `` ndra RacanÄ valÄ `` ) are one of Bengal 's greatest cultural treasures , while Tagore himself has been proclaimed `` the greatest poet India has produced '' . Tagore 's Bengali-language writingsâ '' the 1939 RabÄ `` ndra RachanÄ valÄ `` â '' is also canonised as one of Bengal 's greatest cultural treasures .