What this source establishes
The figure this page has always carried, found at last in print. Besse, from the mission's records, gives the Vadakenkulam church “at least 4128 adults and a large number of children” in 1713, about 800 adult baptisms across 1712–13, and 85 more preparing that October. He states it as a statistic, not as tradition — which is why this moment is documented and no longer the one uncited dot on the page.
This is as much of the book as this site prints. It is named in full in the bibliography below.