▁larger . ▁During ▁John ' s ▁sie ge ▁of ▁Ro chester ▁in ▁ 1 2 1 5 , ▁the ▁south - east ▁corner ▁col lapsed ; ▁during ▁Henry   III ' s ▁reign ▁it ▁was ▁re built ▁as ▁a ▁cyl inder . ▁The ▁windows ▁increase ▁in ▁size ▁higher ▁up ▁the ▁walls ; ▁those ▁in ▁the ▁upp erm ost ▁were ▁decor ated . ▁A ▁spir al ▁st air case ▁in ▁the ▁north - east ▁corner ▁provided ▁access ▁to ▁all ▁flo ors , ▁and ▁another ▁in ▁the ▁south - west ▁corner ▁went ▁from ▁the ▁first ▁floor ▁to ▁the ▁top ▁floor . ▁The ▁north - west ▁corner ▁tower ▁contains ▁small ▁ch amb ers , ▁and ▁the ▁south - east ▁probably ▁had ▁a ▁similar ▁layout ▁before ▁it ▁was ▁re built . ▁ ▁K ee ps ▁were ▁tradition ally ▁built ▁with ▁an ▁entrance ▁at ▁first - floor ▁level , ▁and ▁Ro chester ' s ▁follows ▁this ▁pattern . ▁A ▁for eb u ild ing ▁attached ▁to ▁the ▁north ▁side ▁guard ed ▁the ▁entrance . ▁A ▁stone ▁st air case ▁began ▁on ▁the ▁west ▁side ▁of ▁the ▁keep ▁before ▁turning ▁and ▁meeting ▁the ▁for eb u ild ing , ▁which ▁could ▁be ▁entered ▁by ▁crossing ▁a ▁draw bridge ▁across ▁a ▁gap ▁ ▁wide . ▁There ▁was ▁another ▁entrance ▁in ▁the ▁west ▁of ▁the ▁for eb u ild ing , ▁and ▁at ▁some ▁point ▁a ▁new ▁door way ▁was ▁knock ed ▁through ▁to ▁the ▁keep ▁at ▁the ▁bottom ▁of ▁the ▁draw bridge ▁pit . ▁The ▁original ▁door ▁from ▁the ▁for