Pope Leo V died in 903.
Pope Leo I died on 461-11-10.
If you mean Pope Benedict XVI, Pope Francis followed him as pope.
Pope Leo III died on 816-06-12.
Pope Leo II died on 683-06-28.
Pope Leo IV died on 855-07-17.
Pope Leo VII died on 939-07-13.
Pope Leo XI died on April 27, 1605 at the age of 69.
Pope Leo XII died on February 10, 1829 at the age of 68.
Pope Leo IX died on April 19, 1054 at the age of 51.
Leo the Great died of natural causes. He was not a martyr.
Leo X died December 1, 1521.
Leo V the Armenian died on 820-12-25.