The heart of King Jan III Sobieski is in Warsaw - in the Royal Chapel in the Church of the Transfiguration. In its central part there is an altar with a picture of the Blessed Angel from Accra, brush of the Warsaw painter Jan Gładysz. The guts of Jan III were laid in the sarcophagus, and the king's heart in a silver vessel. The wall is decorated with a bust of Jan III, made of white marble, by Ludwik Kaufmann. The chapel also contains the sarcophagus of Augustus II with the remains of the king.
The design of modernizing the existing chapel in this place was made in 1828 by Henryk Marconi - a respected government architect. The immediate motivation was the desire to find a worthy place for the image just raised on the altar of Bl. Angel of Accra. In addition to propagating his worship, religious also wanted to expose the heart of the king who was still in the monastery's archives. The initiative was supported by Tsar Nicholas I, who covered all the costs of renovation.