Holy Trinity Cathedral gathers its fame as one of the oldest Catholic churches of Kerala and is of great historical importance. The establishment of this cathedral was instrumental to the missionary activities in north Malabar. The history of this ancient Roman Catholic Church dates back to 16th century when a group of four Franciscan missionaries visited Malabar as part of propagating Christianity. These missionaries, with permission from the then rulers, built a chapel in here 1501, and it is believed that the current structure of Holy Trinity Cathedral lies on that spot.
Holy Trinity Cathedral is located in Burnassery, a few kilometers away from Kannur town and is easily accessible by road. The area around Burnassery was previously known as Kannur Cantonment. Apart from Holy Trinity Cathedral, the major attractions around Burnassery include St. Thomas Orthodox Church and Fort St. Angelo. The church has recently been renovated in 2010, and Roman-Gothic style of architecture adds to the beauty of this historic monument.