Prince John Konstantinovich of Russia

Prince John Konstantinovich of Russia, formerly Grand Duke John Konstantinovich of Russia, sometimes also known as Prince Ivan, Prince Ioann or Prince Johan, was the eldest son of Grand Duke Konstantin Konstantinovich of Russia and Yelizaveta Mavrikievna, née Princess Elisabeth of Saxe-Altenburg. He was described by contemporaries as a gentle, religious person, nicknamed "Ioannchik" by his relatives.