The fort was originally built by Maharaja Khem Sawant Bhonsle, the Raja of Sawantwadi, in the 17th century. The site chosen was a hillock on the Northern (right) bank of the river, which gave a commanding view of the Arabian sea. The Bhonsles of Sawantwadi kept a sizeable fleet of native vessels which sheltered in the Tiracol River. The fort initially consisted of 12 guns, a barrack and a chapel. A Church for the Holy Trinity was constructed in the fort courtyard by de Almeida after its capture. This later became the century old Church of St. Anthony.