Martyr
A martyr is someone who suffers persecution and later assassination or death for advocating, renouncing (giving up), or refusing to renounce (not giving up) a religious belief or other cause, despite another person or group demanding that they do so.
Originally it was applied only to those who suffered for their religious beliefs but now the term has come to be used in connection with people killed for a political or nationalist cause as well.
Martyr Media
Miniature from the Menologion of Basil II depicting the 20,000 Martyrs of Nicomedia, who were martyred when Roman soldiers set their church on fire on Christmas Day, AD 302
Charles I is regarded by many members of the Church of England as a martyr because, it is said, he was offered his life if he would abandon the historic episcopacy in the Church of England. It is said he refused, however, believing that the Church of England was truly "Catholic" and should maintain the Catholic episcopate.
Sculpture at Mehdiana Sahib of the execution of Banda Singh Bahadur by Mughals in 1716.[source?]
From the gallery of 20th century martyrs at Westminster Abbey—l. to r. Mother Elizabeth of Russia, Rev. Martin Luther King Jr., Archbishop Óscar Romero and Pastor Dietrich Bonhoeffer.[source?]
A painting commemorating the martyrdom of the 3rd Shia Imam Husayn ibn Ali at the Battle of Karbala in 680 AD[source?]
Interior of the Coliseum at the National Shrine of the North American Martyrs, Auriesville, New York, showing the sanctuary and high altar