 Complete the following phrase:  Jan Skrzetuski is a fictional character created by Polish author Henryk Sienkiewicz in the novel With Fire and Sword. He is a man of honour, always faithful to his master, duke Jeremi Wiśniowiecki. He loves Helena Kurcewiczówna, who was kidnapped by the Ukrainian Cossack Yuri Bohun, who is also in love with her. Skrzetuski is the best friend of Michał Wołodyjowski. Jan Skrzetuski is partly based on a historical character, Mikołaj Skrzetuski, the Polish hero of the 