Organised internal and maritime commerce was an important feature of medieval South India, often resulting in acute trade rivalries and armed conflicts between ruling dynasties who laid great emphasis on trade and conquests within and outside peninsular India. And it were the merchant guilds which provided the institutional framework for organised commerce internally and overseas. The need for a detailed study of history and activities of the merchant guilds for a fuller and objective appreciation of history?of?South?India?is?thus?imperative.The present work is the first detailed study of two powerful medieval merchant guilds of peninsular India, viz., MANIGRAM and AYYAVOLE. The author reconstructs the history of the guilds and analyses their activities through a systematic study of stone and copper inscriptions found in Tamil and Kannada speaking areas of South India, merchant inscriptions in Sri Lanka?and?extensive?travels?in?South-East??Asia.The book throws fresh light on the Cola State synthesis, relationship between merchants and kings and the importance of revenues from tradeto the medieval state and the linkage between South India kingdoms with the?Indian?Ocean?and?sea?borne?trade.Fresh interpretations of political history have been provided; the Cola Wars have been linked to commercial compulsions and the drift of people in Sri Lanka from the northern plains to the South-West coast has been examined?in?the?context?of?changes?in?pattern?of?foreign?trade.