She converted from Roman Catholicism to Judaism or to Judaizing nontrinitarianism,[1] and was executed in Kraków after she refused to call Jesus Christ the Son of God.

She was born Katarzyna Zalasowska, a daughter of Stanisław Zalasowski[2] and widow of Melchior Weigel, merchant and councilman of Kraków.

[3] Little is known about her life before 1529–1530 when she appeared several times before an episcopal court in Kraków, and refused to abjure "mistakes of the Jewish faith".

[4] The burning of Catherine was a surprising incident in Poland, which, in the 16th century, ranked among the countries with the highest degree of religious tolerance.

The Sejm in 1539 did not take a stance on her execution, and mentions of her have been preserved mainly in Protestant polemical writings and in Judeophobic literature from the 17th century.