The Gold and Silver Road of Trade and Friendship: The Mcleod and Richardson Diplomatic Missions Tai States in 1837. When British diplomats McLeod and Richardson set out on their missions to the Tai states in December 1836, their aim was trade and friendship. Captain William Couperus McLeod and Dr. David Richardson, both of the East India Company Madras Army, traveled from Moulmein on elephants, horses, and in the caravans of traders, to the present-day regions of the Shan States in Burma, northern Thailand, and Sipsong Panna in China. As the first Europeans to officially visit the region, they experienced some extraordinary social and cultural encounters.