Gothic basilica whose oldest parts—such as the sacristy—date back to the 14th century, built upon even earlier Romanesque foundations . Over the centuries it has been expanded and richly adorned: its interior features Renaissance chapels (notably from 1607), Baroque altars, 17th–18th‑century tombstones, and stained-glass windows and polychromes by Eligiusz Niewiadomski i (the assassin of the first President of Poland, Gabriel Narutowicz) made in the early 20th century.
Built primarily of brick with sandstone elements, the church still retains visible external buttresses and decorative features like bronze lion-head door knockers from the 15th century. Officially registered as an immovable heritage monument, it remains a central landmark of Konin both architecturally and spiritually.