With the Constantinian shift and the identification of the term Christianity with the Roman Empire, the tables were turned and pagans sometimes became martyrs if they refused the Roman Emperor when ordered to change their beliefs to the Roman Empire's version of Christianity. It didn't take long before Augustine of Hippo authorized the use of force against heretics and Christians who refused to fall in line with Roman Orthodoxy. Persecution of heretics and the martyrdom that sometimes went with it became institutionalised in the office of the Inquisition of the Roman Catholic Church, and in the political systems of the State, such as that of the English Queen Mary I (who became known as Bloody Mary), when she had nearly three hundred Christians tortured and killed (recorded in Foxe's Book of Martyrs) for refusing to denounce their reformist beliefs and for refusing to revert to Roman Catholicism.
Some Christian sects such as Anabaptists as well as non-Christian sects, who began as Christians yet changed their beliefs, trace their origins to widespread persecution and martyrdom at the hands of the Catholic Church trying to suppress their break away sects. The Anabaptists have embraced this part of their heritage to such an extent that the book Martyrs Mirror, which describes the deaths of Anabaptist Martyrs in the 16th and 17th century, is still widely owned and read in Mennonite and Amish households (see Anabaptist persecution for more).
The 20th century again saw large numbers of Christians martyred by non-Christians, in persecutions by political authorities that have antipathy directed towards particular faiths, or religion in general. Allegedly this has included the Soviet Union and early People's Republic of China. The Russian Orthodox Church in post-Soviet times termed many of those who died for this faith "New Martyrs", meaning that it was the 2nd greatest persecution of Christians since I-III AD. The Taliban regime has been known as well to mount another wave of persecutions, although this has received less international attention, given its scale.
Many church historians believe that there were more Christian martyrs in the 20th century than in the first 19 centuries combined. This claim is, however, difficult to confirm for obvious reasons.
See Persecution of Christians for more detail.
Muslims who die in a legitimate jihad bis saif (struggle with the sword, or Islamic Holy war) are typically considered shahid. This usage became controversial in the late 20th century, when (due to the Islamic strictures against Suicide) it began to be applied to suicide bombers, e.g. those belonging to Islamist and Palestinian nationalist groups, whose victims often included civilians. During the Iran-Iraq War, nuptial chambers were constructed to recognized unmarried male soliders killed in the war; according to tradition, this would allow them to attain carnal knowledge. (See also Persecution of Muslims for more detail.)
Other examples include (some disputed):
In the UK the summer of 2005 saw attempts by the Blair government to criminalize the use of the word "martyr" in reference to "Islamist" suicide bombers. This illustrates the polarization surrounding the issue and the need the government obviously felt to break the power of the word.