Alexios I Komnenos or Alexius I Comnenus ( ; ; 1048 â `` August 15 , 1118 ) , Byzantine emperor ( 1081 â `` 1118 ) , was the son of John Komnenos and Anna Dalassena . Alexios I Komnenos , Latinized as Alexius I Comnenus ( , 1056 â `` 15 August 1118 â '' note that some sources list his date of birth as 1048 ) , was Byzantine emperor from 1081 to 1118 , and although he was not the founder of Komnenian dynasty , it was during his reign that the Komnenos family came to full power .