The Romans used indigo as a pigment for painting, for medicinal and cosmetic purposes. It was a luxury, however, being imported from India to the Mediterranean by Arab merchants. The historical record of indigo is patchy, but references were made by Marco Polo who saw indigo at present day Quilon in the state of Kerala in 1298. In 1498 the Portuguese explorer Vasco da Gama discovered a sea route to India . This enabled direct trade with India and the Far East . Until this time trade was conducted over land, the routes were long and dangerous. In Alexandria and Baghdad important cities along the trade routes, Greek and Persian merchants levied heavy taxes on luxury goods like indigo. Opening the sea route bypassed these tax sites and directly resulted in a significant rise in the amount of tropical indigo imported into Europe .
