シュレースヴィヒ＝ホルシュタイン問題
In the army, Jessing rose to the rank of quartermaster sergeant, who proved himself a successful fighter as well as logistician. He was decorated by King William I of Prussia for bravery at the Battle of Dybbøl, earning many decorations and medals for his service in the Seventh Westphalian Artillery during both the First and the Second wars with Denmark over the Schleswig-Holstein Question. Despite all these military achievements, Joseph's dream of ordination remained his true ambition.