Joseph Ratzinger became pope Benedict XVI in 2005 As you probably wouldn t call him Benedict for the period of his life before 2005 because he simply wasn t pope from his birth you shouldn t call Charles emperor when referring to the foundation of the university in 1348 when he obtained this title only in 1355 The fact that he founded the university as King of Bohemia Charles I played eminent role in the history of the institution and therefore is worth mentionig here 13 24 20 Apr 2005 UTC