rebelling against Henry I in the early 12th century. Henry re-granted Pevensey Castle to Gilbert I de l'Aigle but continued to use it for his own purposes, as happened in 1101 when he spent the summer at Pevensey to deter a threatened invasion by Duke Robert of Normandy. Pevensey was confiscated again by the Crown under King Stephen, with Gilbert's family also losing the rest of their possessions. It was subsequently re-granted to Gilbert de Clare, 1st Earl of Pembroke, who switched his allegiance to Stephen's cousin and rival, the Empress Matilda, in 1141. Although Gilbert changed his loyalty back to Stephen the following year, he was taken hostage by the king in 1147 after a revolt by Gilbert's uncle, Ranulf de Gernon, 4th Earl of Chester. A promise to surrender the Clare family's castles secured Gilbert's release but as soon as he was freed, he too rebelled. In response, Stephen undertook the second siege of Pevensey Castle with a land and sea blockade. The castle once again proved impervious to direct assault but the garrison was eventually starved out. Later medieval use Gilbert's disloyalty led to the Crown seizing the castle again and taking on the burden of repairing and maintaining it. The expenditure was recorded in still-surviving Treasury accounts which provide a valuable insight into the development of the castle during the later medieval period. In the 1180s the defences appear to have been a combination of stone walls (the old Roman structure) with Norman modifications, plus earthworks and timber palisades. They were maintained in part by some of the local manors, which were under a feudal obligation called heckage that required them to repair and keep up sections of the palisades. Pevensey Castle appears to have acquired its first major new stone buildings in the 1190s. Their construction may be indicated by a series of substantial payments for works at the castle during the reign of Richard I. The keep and gatehouse may have been constructed under Richard, though mentions from 1130 of "the Tower of Pevensey" suggest that there may have been an earlier stone building on the site, or that the keep was constructed at this earlier date. Whenever it was built, it was probably destroyed by about 1216 when Richard's successor John fought off an invasion led by Prince Louis of France. The French invasion during the First Barons' War forced John to order