In the 1st Century BC, during the reign of King Walagamba, Sri Lanka underwent a famine known as 'Baminithiyasaya' for 12 years. There was also a South Indian invasion at the same time and the Buddhist monks of that era realized that these problems would be a danger to the existence of Buddha Sasana in the country. Under these conditions, memorizing and repeating the Dhamma (doctrine) was difficult. Due to the famine Buddhist monks did not receive sufficient alms and faced many difficulties, and they had to eat yams, roots and leaves of trees for their survival. A group of about 60 of them went to Malaya Rata, which is said to be the hilly area of the country. They managed to live on the banks of Mahaweli river under harsh conditions and survived for 12 years till the famine came to an end.