Complex sentence: After his death in battle on June 26,363, officers of the army elected the Christian Jovian as his successor, who in his precarious position, far from supplies, ended the war with Persia unfavorably for Rome.
Split into simpler sentences: After his death in battle on June 26,363, officers of the army elected the Christian Jovian as his successor. Jovian, in a precarious position, far from supplies, ended the war with Persia unfavorably for Rome.