The giant grain-haulers of Roman times were not Rome’s only large ships — the ancestors of the Dravidians wrote poetry referencing the wonderful ships of the westerners, arriving in India to trade — but the grain-haulers were often the method of choice for travellers coming home from the east, because they had roomy decks and didn’t pitch as much. Lucian included info about one of the grain haulers which had to put in at the Piraeus of Athens, a port which had once serviced smaller but still large grain haulers in the heyday of Greece.
Works of Lucian, Vol. IV: The Ship: Or, The Wishes
http://www.sacred-texts.com/cla/luc/wl4/wl407.htm