It is one of the oldest and most significant monuments of Kőszeg.

Some parts of the edifice date back to the 14th century; the Garais, the oligarchs of the town in the early 1600s, had it reconstructed. From the mid-1700s, when the Reformation movement reached Kőszeg, the church was used by protestants up until 1671 when the Catholics reclaimed it from the Lutherans.The Baroque facade received its current design in the early 19th century; the niche on the front of the church is decorated by the statue of St Jacob, the patron saint of pilgrims and the national saint of Spain.

Over the centuries the church served as a burial place for many celebrities; Captain Miklós Jurisics, who defended the castle against the Ottoman army, had a marble plaque made in 1538 in memory of his son and daughter who had perished in the plague. The plaque has been preserved to this day. According to the latest research, Captain Jurisics himself was laid to rest in the church. The hero of Kőszeg came from a Croatian noble family; he had been member of the Upper House in Vienna and was an active politician and diplomat commissioned by the emperor from 1524. In 1532, when Sultan Suleiman led an expedition to capture Austria, Jurisics was serving as captain in the Castle of Kőszeg. With only 700 armed soldiers at his disposal, he managed to defend the castle to the very end until the Ottoman army had to reconcile and retreat. As a reward for his heroism, the emperor bestowed upon him the rank of baron with the first name of Kőszeg, and a few years later he was granted the castle of Kőszeg.

Another famous historical figure was put to rest in the church: Mária Széchy, the widow of palatine Ferenc Wesselényi also known as the Venus of Murány was buried here in the 17th century. The romantic love story of the couple has served as a source of inspiration for many authors. Mária Széchy came to Kőszeg on 14 October 1676 at the age of 66. She spent her first night in town at the Inn to the Ostrich. She had no other choice but to move here; a few years earlier the Wesselényi conspiracy had come to light and she, as the widow of the palatine, was also involved.  In 1669, in a declining mental state and burdened with substantial debts, she learnt that the conspirators had been exposed. She begged the monarch for mercy but despite admitting guilty Emperor Leopold I had her thrown into prison in 1671 and was held captive for five years. She submitted a request during her captivity that she could be allowed to return to Hungary,which is how she was eventually permitted to move to Kőszeg. According to the Catholic death certificate, Mária Széchy passed away on 18 July 1679 and, following a brief debate, her body was put to rest in the Church of St Jacob.