The Periplus Maris Erythraei or Periplus of the Erythraean Sea provides a fascinating insight into many aspects of the wider Indian Ocean trade in the mid-first century CE. This text was the product of a man who, while he certainly had direct experience of trading in the western Indian Ocean, combined his own knowledge with information gleaned not only from other members of the large and diverse mercantile community based in Alexandria, but also from active traders originating from East Africa, southern Arabia, India and beyond. Here De Romanis analyses these likely sources of information which informed the author in his description of the west coast of India.