It was made of sandstone and limestone in the 15th century. On the stone baptismal font you can see two coats of arms - coat of arms of the Opole-Racibórz principality and coat of arms of Opole. This is undoubtedly the oldest image of the city's coat of arms. There is a half Piast eagle on it, referring to the Opole rulers of the stronghold and half cross, referring to the relics of the Holy Cross, for which the collegiate church in Opole is famous. Below is the stone mason's mark, i.e. his personal mark. It is proof of the generosity of the last of the Opole Piast prince Jan Good.

Until recently, the historic baptismal font stood near the entrance to the Opole cathedral, in the Chapel of Saint John of Nepomuk. During the renovation of this chapel, the stone monument was moved near the main altar, to the northern nave. Today stands in front of the altar of the Holy Trinity. Here again, it serves subsequent generations, which in this place - through the grace of baptism - are included in the Christian community of the Church.