Konstantinos XII (August 2, 1868 to January 27, 1951) was King of the Hellenes (Emperor of the Hellenes after 1945) from the assassination of his father, Georgios I on March 18, 1913 until his death on January 27, 1951 , when he was succeeded by his son Georgios II. His 38-year reign saw the expansion of Greek territory, the realization of the Megali Idea and the capture of Constantinople after 490 years of Ottoman rule.
After his accession as Emperor of the Hellenes in 1945, his regnal name was retroactively changed to Konstantinos XII in order to emphasize continuity between the Byzantine and Hellenic empires.