Battle of the Camps

The Battle of the Camps was an early battle in the War of the Five Kings. It was the second stage of the liberation of Riverrun castle which, following immediately after the Battle of the Whispering Wood, which smashed the House Lannister army that encircled Riverrun and allowed the Riverlords to join their forces with those of the North. It occurs off-screen between the ninth and tenth episodes of the first season of Game of Thrones.

In the books
In order to maintain an effective siege, the Lannister armies were divided into three different camps around Riverrun. Robb Stark lead an assault on one, while Catelyn's uncle Brynden "The Blackfish" Tully led an assault on the second. Caught while asleep, the now-leaderless Lannister armies are easily slaughtered. The third and southernmost of the Lannister camps, which was also the smallest with only 2,000 footmen, did not engage in combat. Seeing that the battle was already lost, it managed to retreat in good order back to Golden Tooth. Nonetheless this meant that barely a sixth of the infantry and none of the cavalry deployed by the Lannisters around Riverrun survived the assault. Tywin, Tyrion, and the rest of the Lannister generals considered it a complete disaster and that their second army-group in the Riverlands had been functionally destroyed.

The Battle of the Camps and the lifting of the siege of Riverrun actually happen within the first novel, A Game of Thrones. By the second season premiere, Jaime Lannister notes that Robb has won three victories, thus implying that the Battle of the Camps has happened between seasons. It also appears that the Battle of the Camps happened "off screen" as did the Battle of Whispering Wood, as later in the same episode the at the Lannister war council, Tywin and his generals state that Jaime's army was destroyed.