An inscription on a stone plaque in the southern wall of the tower states that the extension of the church began in 1408. A three-bay, three-aisled hall nave and a tower were added to the western wall of the older granite church. The new nave was crowned with a monumental eastern gable, which can still be seen in the church attic today.
It is believed that the original granite chapel was not demolished until the last quarter of the 15th century, when a hall chancel with an apse was built in its place. At the beginning of the 16th century, low chapels were added between the buttresses of the side aisles.
Elements of the original furnishings have survived in the church to this day. The tower houses the largest medieval bell in Western Pomerania, the third instrument of its class in Poland. The bell, known as Jan Maria, was cast in 1464, probably to celebrate the peace concluded between Stargard and Szczecin after the Wheat War. Its lower diameter is 178 cm and it weighs 3,876 kg.
