 On August 28–29, the start of the Second Battle of Bull Run (Second Manassas), Pope launched repeated assaults against Jackson as Longstreet and the remainder of the army marched north to reach the battlefield.On August 30, Pope came to believe that Jackson was starting to retreat, and Longstreet took advantage of this by launching a massive assault on the Union army's left with over 25,000 men.Although the Union troops put up a furious defense, Pope's army was forced to retreat in a manner similar to the embarrassing Union defeat at First Bull Run, fought on roughly the same battleground.