When she was young she married the powerful William of Rosenberg, who was however already sick and sterile. After his death, she acquired substantial assets within settlement arrangements with her step-brother Peter Vok. She used her wealth to support her poor Pernstein relatives. Polyxena herself supervised management in the estates of Roudnice and Litomysl. Following the death of her brother Jan of Pernstein in 1597, she took his children into custody. She became a much respected woman and entered popular consciousness for her fervent catholic faith.
In 1603 she married the highest
Lobkowitz chancellor, who was the head of the catholic nobility and a faithful supporter of Ferdinand II of Styria as a candidate. In 1618 Polyxena gave shelter in her house in Prague to the victims of the second Defenestration of Prague. She distinguished herself as the benefactor of various holy orders and after the confiscations she bought back numerous belongings of the Estates nobles. She invited the Jesuits to establish on her domains and spread catholic faith. In 1628 she donated the precious statuette of the famous Infant Jesus to the Carmelites of the Church of Our Lady.
