The Sovabazar Rajbari puja is usually cited as the first Durga Puja held in Kolkata by an Indian family, dating to 1757 — the same year the East India Company defeated Siraj-ud-Daulah at the Battle of Plassey. Its founder, Raja Nabakrishna Dev, had worked closely with the British in the years leading up to that battle (he had served as a munshi, or clerical assistant, to Warren Hastings), and the puja is remembered as much as a victory celebration as a religious one — thrown, by most accounts, partly to host Robert Clive and other East India Company officers at the newly built Sovabazar palace.
More than 250 years on, the puja still runs to its own fixed customs rather than the yearly theme changes that define most modern pandals. The idol is made in the traditional ekchala style — all of Durga and her children framed within a single arched backdrop — every year, without variation. One local detail that regularly surprises visitors: the lion at the goddess's feet is given a horse's face (locally called Gotokmukhi Singha) rather than the usual lion's head, a quirk specific to this rajbari's idol.
The ritual calendar has its own fixed set-pieces too: a Kalabou Snan procession that carries the ceremonial banana-plant "bride" to the Ganges under a red velvet umbrella, 108 earthen lamps lit on Ashtami night preceded by ceremonial gunfire, and — on immersion day — a custom in which two boats are used and deliberately allowed to separate mid-river. The puja is held inside a thakur dalan, an open columned hall built specifically for this kind of worship, within the rajbari itself.