[7] In 1621, Bernardino Castillo, a generous patron and a devotee of the 3rd-century Roman martyr Saint Sebastian, donated the land upon which the church stands.

[3] According to historian Ambeth Ocampo, the knockdown steel parts were ordered from the Societe anonyme des Enterprises de Travaux Publiques in Brussels.

[5] Upon its completion the following year, on August 16, 1891, the Basílica Menor de San Sebastián was consecrated by Bernardino Nozaleda y Villa OP, the 25th Archbishop of Manila.

[5] According to Jesús Pastor Paloma, an Augustinian Recollect priest, the structure was also supposed to have a prefabricated retablo (reredos) altar, which was lost at sea when the ship carrying it from Belgium capsized in a storm.

[5] The faux finished interior[6] of the church incorporates groined vaults in the Gothic architecture style permitting very ample illumination from lateral windows.

[3] The steel columns, walls and ceiling were painted by Lorenzo Rocha, Isabelo Tampingco and Félix Martínez[6] to give the appearance of marble and jasper.

[8][6] True to the Gothic revival spirit of the church are its confessionals, pulpit, altars and five retablos designed by Lorenzo Guerrero[14] and Rocha.

[16] Above the main altar is the ivory statue of Our Lady of Mount Carmel, given to the church by Carmelite sisters from Mexico City in 1617.

[5] The image withstood all the earthquakes and fires which had destroyed previous incarnations of San Sebastian Church, but its ivory head was stolen in 1975.

[5] San Sebastian Church was declared a National Historical Landmark by President Ferdinand Marcos through Presidential Decree No.

To re-establish the site's integrity and re-inclusion in the tentative list, it underwent a massive restoration program, which conservationists have cited as a megalithic success.