King Richard the Lion Heartedís brother, King John, lost Chateau Gaillard but gained Rochester Castle (see Figure 6). The barons who opposed King John and forced him to sign a charter of rights (Magna Carta) in 1215 had taken control of Rochester Castle. The king laid siege to it. His troops kept up a steady barrage, hurling rocks with their siege machines, but the garrison threw the missiles back from the battlements with such force and accuracy that they killed the royal troops at an alarming rate. The kingís men changed tactics and began to mine the curtain wall. The mining proved successful, and the troops rushed through the breach in the wall to engage the garrison in hand-to-hand combat. The outnumbered rebels retreated to the Norman tower. The miners then went to work again and brought down the southwest corner. But the garrison continued to fight, driving back the royal forces time after time. Supplies ran out in the tower, and the starving garrison finally surren dered after a siege lasting nearly three months. The southwest turret was rebuilt as an up-to-date round tower.