Appolonia Jagiello was born in Poland in 1825. Much of her early life is unknown, or was romanticized following her eventually immigration to the United States. According to one source, Appolonia was born in Lithuania (then part of the Polish–Lithuanian Commonwealth) and was educated in Krakow. During the Kraków uprising of 1846, she disguised herself as a man and joined the Polish army. The uprising was eventually crushed by the combined powers of Austria and Russia, but Jagiello was able to re-assume female dress and escape. Jagiello made her way to Hungary after the conflict and took part in the Hungarian Revolution of 1848, again fighting against the Austrian Empire. During the conflict, she was eventually promoted to be the superintendent of a military hospital at the Fortress of Komárno, which the revolutionary army had captured. When the revolution was suppressed by the Austrians, Jagiello immigrated to the United States, joining a large number of Polish, Lithuanian and Hungarian emigres who had also fled Europe.