With the emergence of the Sree Padmanabha Swamy Temple under Anizham Thirunal Marthanda Varma, the once small Darpakulam was expanded, a pond fed by natural springs, the exact dimensions of which can be found in the records of Mathilakam. Thus, during the 18th century, the conversion of the old Darpakulam to present-day Padmatheertham was initiated. The introduction of Murajapam and Lakshadeepam festivals, which ensured the participation of numerous scholars and dignitaries from all over Kerala, is said to have been the key reason for the pond's enlargement.Further, the pond was equipped with a constant supply of fresh water from the Maruthankuzhi-ana in Killi river by means of a channel known as Cochar.
Padmatheertham keeps in its depths many fascinating titbits of history linked to the Sree Padmanabhaswamy temple and the royal family of erstwhile Travancore. During the reign of Dharmaraja (1758-1798), Makayiram Thirunal, the King's brother, drowned in the tank a spy from Mysore who settled in the Fort in the guise of a mendicant with magical abilities. The tank has a small vault, where some sâlagramams are still kept for the creation of the idol of Sree Padmanabhaswamy. Later, Sree Moolam Thirunal Rama Varma (1885-1924) made arrangements to store water from rivers considered sacred within the vault, from all over India, enhancing the sanctity of the ancient body of water.
In the later years the serene Padmatheertham has changed. The old drainage system became obsolete, and iron railing and gates across the pond were built. The introduction of new elements triggered a change in the relationship between the locals and the bay. A few old-timers continued to visit their hangout – the pond's fond memories, the camphor and incense fragrance, and the air-floating music.