St. Thomas the Martyr is the parish Cof E church, named after Thomas Becket, located in Winchelsea, East Sussex.
Construction of the church was started in 1288, close to the centre of the new town of Winchelsea. Building stone was imported from Caen in Normandy, the marble used was from west Sussex and the oak was sourced locally.
In 1380, a Franco-Castilian fleet arrived at Winchelsea with plans on burning the town to the ground. They caused severe damage to the church. Over the next 100 years the church was left to decay, the tower and transepts collapsed. The west end of the church was blocked off and a new entrance porch was built.
In the 16th Century, during the Reformation, the Dominican and Franciscan property endowed to the church, including the hospital, were confiscated and later pulled down. The church was left derelict and by 1660 the church was almost in ruins.
As the town of Winchelsea was in decline, the church was left in a poor state, although still used, only minor repairs were made. By 1850 the church was so dilapidated that it was declared unfit for worship and extensive repairs were carried out.
Stain glass windows were installed in the 1920's as a war memorial for the solders of the Cinque Ports who lost their lives in World War I.