The fort at Thangasseri in South Kollam was declared a monument of national importance under the Archaeological Survey of India Act 1958.
Thangasseri in South Kollam was of strategic importance to the colonial powers in the struggle for dominance of trade on the Malabar Coast. History records that the Portuguese originally approached the Rani of Quilon in 1517 to build a factory at Thangasseri for the purpose of trade, which was granted.
The factory it is said was later burnt down by the natives, and permission was given to repair the factory. But the Portuguese under Commandant Rodrigues built a fort instead.
Built in 1519, the gaunt fort, standing on a promontory overlooking the sea, is a mute witness to the rise and fall of colonial regimes on the West coast and is a relic of the colonial phase in the history of Kerala. The fort was declared a monument of national importance under the Archaeological Survey of India Act 1958 and is under the administration of the ASI, Thrissur Circle.
The fort as it appears today is just a fragment of the central tower of the fort. Built of laterite and lime-plaster, the wall measuring about four feet in thickness, is about 50 feet in height. Originally said to be two and a half furlong in length and a furlong in breadth, the Dutch it is said diminished the size of the fort.
Remnants of the fort wall and the moat, submerged in the sea can be seen at places, extending in an arc along the coast northwards. Besides being the storehouse for goods, soldiers were also stationed at the fort.
There was also a canal between the beach and fort, for conveyance of goods by country craft. The canal which is largely extinct was called the Buckingham canal. Two dilapidated Europeans cemeteries, which lie within the precincts of the fort, containing tombs of the Military dating from the early eighteenth century and the ruins of an old Portuguese tower, are the only vestiges of the Colonial times, apart from a lighthouse built by the British in 1902.
Thangasseri was successively under the Dutch who defeated the Portuguese in 1761 and then passed into British hands with the defeat of the Dutch at Kochi in 1795.
The Archaeological Survey of India, Thrissur Circle, has drawn up an Expert Committee under the superintending archaeologist Dr. Nambirajan, which will make an on-the-spot study to conduct overall repairs and conservation of the monument. Maintaining the authentic character of the fort, for instance by using lime-plaster and laterite as of old, will be the guiding principle. Protection and maintenance of the natural setting are among other vital considerations. (Ref. C.A. Innes, I.C.S. Malabar Gazettteer).