The Third Campaign refers to a significant military operation during the Napoleonic Wars, specifically the Russian Campaign of 1812. This campaign was led by Napoleon Bonaparte and aimed to invade Russia to compel Tsar Alexander I to rejoin the Continental System. The campaign began with a massive army, known as the Grand Army, crossing the Neman River. However, the Third Campaign faced numerous challenges, including harsh weather, supply shortages, and strategic retreats by the Russian forces. The turning point came with the disastrous retreat from Moscow, leading to heavy losses for the French army. Ultimately, the campaign marked a significant decline in Napoleon's power and influence in Europe.