There are hundreds of martyrs who died in a number of gruesome and grisly ways. A more specific answer requires a more specific question.
martyrs are people who die for there religious faith
The martyrs died for their christian belief.
Wexford Martyrs died in 1581.
Oxford Martyrs died in 1555.
Leontine martyrs died in 455.
Canterbury Martyrs died in 1555.
Martyrs of Abitina died in 304.
Uganda Martyrs died in 1918.
Martyrs of Thailand died in 1940.
Vietnamese Martyrs died in 1625.
Drina Martyrs died in 1941.
Perth Martyrs died in 1543.