 Inside, the most valuable element of the original church's decoration are the preserved fragments of a brilliant tomb monument of Maria Karolina Sobieska de Bouillon carved by Lorenzo Mattielli in white and black marble in 1746.The effigy of the founder in an oval frame was placed atop the plinth with the Janina coat of arms and a royal crown.The whole composition was completed with carved statues of the personification of the Polish–Lithuanian Commonwealth and a putto, while the arcade above was adorned with skulls.