The painting of St. Clement of Rome was probably created in the first half of the 19th century and it was designed for the high altar. St. Clement of Rome was the third Pope after St. Peter (88-97). He is presented in attire in accordance with this dignity. According to reports, Emperor Trajan sent Clement into exile to Chersonesus (the Crimea) and then sentenced him to death by drowning in the Black Sea with the anchor around his neck, which is why it is his attribute.
Paulina Kluz, "St. Clement of Rome", [in:] "The Sacred Lesser Poland Heritage", 2022, source: https://sdm.upjp2.edu.pl/en/works/st-clement-of-rome-1