I passed over a narrow stagnant canal and then did a double take. I walked back over the small bridge to take a photo, because my phone showed that this was the storied Calvetti canal (alternately Kalvathy or Calvathy). The history of Kochi as we know it starts from a massive flood coursing down the Periyar river in 1341 CE and realigning the coast around where I took the featured photo. That put an end to the port of Muziris, which had been a stop on the maritime silk route, and a center of commerce with the east and west for 14 centuries. But it was also the birth of the new port of Kochi, which would remain an important part of the Indian Ocean trade during the late medieval and early modern era. After 1341, the Calvetti canal was the channel through which an immense amount of East-West trade passed; an earlier equivalent of today’s Malacca Strait.
The proper form of the name is Kalvetti, usually interpreted to mean `a stone cutter’. But Mr. V. K. Raman Menon of Tripunittura, Cochin, who has kindly supplied an exhaustive note on the subject, writes that the name means `Hangman’s Canal or Island’ (kazhu ettuku, `to impale’), impalement, not hanging, being in ancient times the mode of execution.
— Travels in India, Jean-Baptiste Tevernier (footnote in the English translation of 1889).
The Indian Ocean trade, bolstered for a while by Ming treasure fleets, made Kochi a wealthy medieval port town, through which most of the trade of the Deccan flowed. The importance of Kochi becomes apparent from a collection of old maps of Fort Kochi in the Mattancherry Palace (an example above), one from every European trading power. Most of them show the Calvetti canal as a wide watercourse. As I stood on the narrow British-era bridge and looked at the nullah (Hindi for drainage ditch, Wikipedia has it wrong again) that it has become, I wondered when it began to be filled in. Certainly before the bridge was built. At least on this eastern side of Kochi there is a remnant of the Calvetti canal; on the western end it has been completely built over, so that Fort Kochi is no longer an island. What a difference a few centuries can make.