▁fort ▁built ▁in ▁the ▁city ▁between ▁ 1 5 6 1 ▁and ▁ 1 5 6 3 ▁on ▁the ▁orders ▁of ▁Duke ▁Cos imo , ▁a ▁few ▁years ▁before ▁he ▁became ▁the ▁first ▁Grand ▁Duke ▁of ▁T usc any . ▁ ▁The ▁for tr ess ▁is ▁position ed ▁on ▁the ▁northern ▁edge ▁of ▁the ▁central ▁S ien a ▁in ▁the ▁Ter zo ▁of ▁Cam oll ia , ▁in ▁the ▁neighborhood ▁of ▁San ▁Pro s per o , ▁and ▁since ▁ 1 9 2 3 ▁has ▁over look ed ▁the ▁city ’ s ▁Ar tem io ▁Fran chi ▁/ Mon te pas chi ▁Arena . ▁ ▁History ▁ ▁Const ruction ▁of ▁the ▁for tr ess ▁followed ▁the ▁Battle ▁of ▁Mar ci ano ▁which ▁in ▁ 1 5 5 4 ▁marked ▁the ▁final ▁defeat ▁of ▁S ien a ▁by ▁its ▁long - standing ▁rival , ▁Florence . ▁▁ ▁It ▁was ▁located ▁on ▁the ▁site ▁of ▁a ▁previous ▁fort , ▁known ▁as ▁the ▁C itt ad ella / C it adel , ▁which ▁had ▁been ▁built ▁in ▁ 1 5 4 8 ▁on ▁the ▁orders ▁of ▁the ▁Emperor ▁Charles ▁V ▁after ▁the ▁city ▁came ▁under ▁the ▁control ▁of ▁Spain , ▁subject ed ▁to ▁the ▁authority ▁of ▁the ▁Spanish ▁amb assador , ▁Diego ▁H urt ado ▁de ▁M endo za . ▁ ▁On ▁ 2 6 ▁July ▁ 1 5 5 2 ▁the ▁S ien ese ▁rose ▁up ▁against ▁the ▁Spanish , ▁exp elling ▁them ▁from ▁the ▁city ▁and ▁destroy ing ▁the ▁Cit adel / C itt