Complex sentence: In his youth, François learned his father's trade, and married Bérénice Thérèse Ménard originally of Cahokia (Kaskaskia, Illinois) on 12 July 1819 in St. Louis before heading west into the frontier.
Split into simpler sentences: In his youth, François learned his father's trade. He married Bérénice Thérèse Ménard originally of Cahokia (Kaskaskia, Illinois) on 12 July 1819 in St. Louis before heading west into the frontier.