Several Hindu shrines in the Tamil country were destroyed during the occupation, particularly under Philip II, when Trincomalee became the scene of naval battles during Europe's Thirty Years' War.

King Ethirimana Cinkam of the Jaffna kingdom had resisted a call by D. Jerónimo de Azevedo in 1612 to aid the latter in building a fortress in Trincomalee.

[2] With the defeat of King Cankili II, all of the territory of the kingdom of Jaffna, comprising Trincomalee and Batticaloa, was assigned to the "spiritual cures of the Franciscans."

[3] By the end of 1619, a small Danish fleet had arrived at Trincomalee; in May 1620, the Danes occupied Koneswaram temple and began works for the fortification of the peninsula before being defeated.

[1] The main statue was taken out to town during the 'ther' (chariot or car) procession, during which time Portuguese soldiers entered the temple dressed as Iyer priests and began robbing it.

Temple stones and its carved pillars were used to construct Fort Fredrick to strengthen the colonists' influence over the eastern seaboard of the island against other invading European armies, including the Dutch navy during the Dutch–Portuguese Wars.

Trincomalee witnessed several naval battles of Europe's Thirty Years' War under Phillip II's man Filipe de Oliveira.

[10] A site plan by De Queiroz states: "On the first rise to the summit of the rock was a Pagoda, another at mid-ascent, and the principal one of them all at the highest eminence, visited by a concourse of Hindus from the whole of India.

While on the north side the third bastion was connected with that of Sancto Antonio only by a parapet of "pedra and cal" situated on the top of the rock cliff to the sea, the Portuguese had modified the escarpment below this wall so as to render it steeper.

The soldiers resided inside of the fortress together with their captain, while the captain of the fort that was named by the King or by the Viceroy, resided in a house in the settlement of the casados.18 In accordance with a map in the "Livro das plantas das fortalezas cidades e povoaçois do Estado da India Oriental" another isolated bastion was present on the south side of the rocky promontory.

Costantino de Sá informs us that on the three bastions were mounts 16 pieces of artillery, the garrison comprised 40 soldiers and 30 casados.