Duke Christian Louis of Mecklenburg was the second son of the last reigning Grand Duke of Mecklenburg-Schwerin, Frederick Francis IV.
Pictured in 1918 (on right) with his mother and elder brother.
Prince William Victor Charles Augustus Henry Sigismund of Prussia, was the second son of Prince Henry of Prussia and Princess Irene of Hesse and by Rhine. He was the nephew of Kaiser Wilhelm II and Tsarina Alexandra of Russia. As the great-grandson of Queen Victoria through both his parents, he was the only one of three brothers who did not have the hemophilia common among her descendants.
Sigismund with his older brother and their parents.