Like Bangladesh and India, Rabindranath Tagore is the writer of Sri Lankan National Anthem too. We all knew that, Rabindranath is the writer of national anthem of Bangladesh and India. But it is now newly explored that, he is the writer of Lankan anthem too. News reported in Bangla News 24.
Basically, a student of Tagore named Samarkun has translated a Bengali Rabindra song before while Sri Lanka was not independent. Sri Lanka was a British colony before their independence in 1948. Samarkun was studying in Biswabharati where Tagore was his teacher. Once, Samarkun requested his teacher to write a song for his country.
Then Rabindranath Tagore wrote down the song in Bengali. Samarkun translated it and the translated version approved by the committee on national anthem.