Petersen grew up in the southernmost city of
Christianssand and graduated from the local cathedral school in 1810. He studied law at the
University of Copenhagen and got his law degree there on 14 January 1814—the day the
Peace Treaty of Kiel was signed, thus ending four hundred years of Danish-Norwegian union. Petersen now wanted to return home to participate in the fight for independence, but the sea route was blocked and on Swedish territory he would be demanded to swear allegiance to the Swedish King. Together with several others – one of them his later wife – he crossed by rowing boat to Sweden, before continuing over land to Christiania disguised as a coachman. == Early career ==