The Hill Palace was built in the year 1865 by the erstwhile Maharaja and is now the largest archaeological museum in the state of Kerala. Before Tripunithura, the capital of the Cochin kingdom and the royal office was located in Thrissur. However, the royal family of Cochin had a matrilineal custom. This means that the queen was the sovereign of the state, and the king ruled under her authority. After 1775, the queen and her assistants moved to the city of Tripunithura, thereby shifting capital to the new city. Later, the kings started preferring to stay at Tripunithura, leading to the construed a new royal office in 1865. Gradually, court buildings, secretary office and various other official and residential buildings were constructed.The magnificent Hill Palace was later on handed over to the Kerala government by the royal family in 1980 and was taken under control by the Department of archaeology. They converted the palace into a museum, and it was first opened for public viewing in the year 1986.