John Jagiellon Bishop of Poznań and illegitimate son of Sigismund I the Old, King of Poland (1499–1538) Parents Katarzyna Telniczanka Sigismund I the Old Children Siblings Catherine Jagellon Beata Kościelecka Wojciech Olbracht Sigismund II Augustus Hedwig Jagiellon, Electress of Brandenburg Katharina of Poland, Countess of Montfort Regina Szafraniec Isabella Jagiellon Sophia Jagiellon, Duchess of Brunswick-Lüneburg Anna Jagiellon Anna Jagiellon
