Church of St. Adalbert was created in the style of the Mazovian Gothic after 1546, thanks to the foundation of Benedictines from Płock. The construction of the church could not begin until the works at the Płock Cathedral were completed, from which bricklayers and building materials from the chapter brickyard were transferred. By 1822 Benedictine monks from the monastery in Pułtusk took care of it. In 1618 the tower gables were transformed. The church was renovated several times in the 19th and 20th centuries when a neo-Gothic porch was added to the southern façade.
The building is a three-aisle basilica with an elongated, straight ended chancel and a five-storey tower on the facade. The four-bay nave is based on a plan close to rectangular and is covered by a common roof with a three-bay chancel, equal to the width and height of the central nave. The northern aisle was extended with a chapel, sacristy and vestibule with the Milbergs’ tomb crypt, while an annex with a staircase to the tower was attached to the southern aisle. The corners of the nave, presbytery and tower as well as the façades of the aisles were clasped with buttresses. The eastern facade of the presbytery is crowned with a stepped gable filled with rows of semicircular blendes. Originally, in its center there was a window set in a deep niche closed with a full arch. The interior of the church was covered with a wooden ceiling.
The unusual structure of the church in Szczepankowo is the west tower in which rooms heated with fireplaces were placed (probably intended for the Benedictines from Płock managing the church) and the western gallery. This building resembles castle or town towers, although it had no defensive features. The lower floor received on both sides quite deep niches and the main front entrance to the church. The interior of the church was connected to the tower first floor by means of stairs hidden in the annex at the front wall. The first floor of the tower was occupied by a small room opened into the interior of the church with a large, semi-circular arcade and illuminated by two windows from the west and one from the south. It was warmed by a fireplace. Stairs in the thickness of the north wall led to the upper floor. From their platform, in the north-west corner of the tower, a short diagonal passage was placed in the thickness of the buttress, ending with a currently walled up portal. It probably served to preach to people gathered in the cemetery. The next floor also housed a room illuminated by three windows and equipped with a fireplace. Stairs in the thickness of the northern wall, and then the eastern wall led from it to the church attic from which you could enter the third floor of the tower, without a fireplace, but illuminated by two windows. Finally, the stairs from the attic in the north wall led to the top fourth floor of the tower, with six window openings. This floor was intended for bells.
Kunkel R.M., Architektura gotycka na Mazowszu, Warszawa 2005.
Żabicki J., Leksykon zabytków architektury Mazowsza i Podlasia, Warszawa 2010.