I first heard of Dhudor Ali, the Lazy Man's Road, while living in Guwahati, and reading a history of Assam by Dr Swarna Lata Baruah. I read about the Ahom period, which began in 1228 when Sukapha, a chieftain from Mong Mao (somewhere around the present day boundaries of Assam, Myanmar, China's Yunnan region, and Arunachal Pradesh) crossed the Patkai mountains with several thousand soldiers and settled in upper Assam. He and his successors would rule Assam for six hundred years, influencing and being influenced by the tribes who already lived in the fertile Brahmaputra valley.
