Unitarian martyrs are individuals who died for their adherence to Unitarianism, a theological position which claims to derive from the Christian Bible and denies the Trinity, instead maintaining that there is one God in one person (the Father). And in modern times as the Unitarian moment broadened to embrace more than simply Christianity, Unitarian martyrs may rightly now also included, individuals who died for their adherence to Liberal religion. Following is a partial list ordered by date of some of these martyrs.
260 AD: Dionysius of Alexandria - was denounced at Rome for calling Jesus a "creature of God." Later (likely due to pressure), he recanted.
336 AD: Arius - claimed to have been murdered by a mob in the streets of Constantinople shortly after Constantine I's death. However other accounts suggest that he was poisoned or that he was not murdered at all (see the article on Arius).
339 AD: Eusebius of Caesarea - is suspected to have been murdered; his Ecclesiastical History ends abruptly with the death of Constantine I. In any case he was definitely excommunicated
476 - 1000 AD. - Dark Ages. Little history recorded.
There is a lot of recorded history for this period, some relates to the Unitarian belief, or questions regarding the Trinity.
1529: Ludwig Haetzer - beheaded in Konstanz, Germany; believed Jesus was a leader and teacher, not a God due worship
1553: Michael Servetus - burned at the stake after a prison term because of writing a book criticizing biblical evidence for a Trinity.
1579: Francis David - Lutheran pastor in Transylvania; after Unitarian King John Sigismund died, orthodox views regained power. Francis David was placed in prison, where he ultimately died.