ound ▁m idd ay , ▁a ▁small ▁team ▁of ▁Vol unte ers ▁and ▁F ian na ▁É ire ann ▁members ▁swift ly ▁captured ▁the ▁Magazine ▁Fort ▁in ▁the ▁Phoenix ▁Park ▁and ▁dis ar med ▁the ▁gu ards . ▁The ▁goal ▁was ▁to ▁se ize ▁weapons ▁and ▁blow ▁up ▁the ▁am mun ition ▁store ▁to ▁signal ▁that ▁the ▁R ising ▁had ▁begun . ▁They ▁seized ▁weapons ▁and ▁plant ed ▁explos ives , ▁but ▁the ▁bl ast ▁was ▁not ▁big ▁enough ▁to ▁be ▁heard ▁across ▁the ▁city . ▁The ▁ 2 3 - year - old ▁son ▁of ▁the ▁fort ' s ▁commander ▁was ▁fat ally ▁shot ▁when ▁he ▁ran ▁to ▁raise ▁the ▁alarm . ▁ ▁A ▁cont ing ent ▁under ▁Se án ▁Con n olly ▁occupied ▁Dublin ▁City ▁Hall ▁and ▁adjacent ▁buildings . ▁They ▁attempted ▁to ▁se ize ▁neighbour ing ▁Dublin ▁Castle , ▁the ▁heart ▁of ▁British ▁rule ▁in ▁Ireland . ▁As ▁they ▁approached ▁the ▁gate ▁a ▁l one ▁and ▁un ar med ▁police ▁sent ry , ▁James ▁O ' B rien , ▁attempted ▁to ▁stop ▁them ▁and ▁was ▁shot ▁dead ▁by ▁Con n olly . ▁According ▁to ▁some ▁accounts , ▁he ▁was ▁the ▁first ▁cas ual ty ▁of ▁the ▁R ising . ▁The ▁reb els ▁over power ed ▁the ▁soldiers ▁in ▁the ▁guard room , ▁but ▁failed ▁to ▁press ▁further . ▁The ▁British ▁Army ' s ▁chief ▁intelligence ▁officer , ▁Major ▁I von ▁Price , ▁fired ▁on ▁the ▁reb els ▁while ▁the ▁Under - Secret ary ▁for ▁Ireland , ▁Sir ▁Matthew ▁Nathan ,