Kiddush Hashem (Hebrew: קידוש השם, lit. "sanctification of the Name") refers to a Jew's readiness to sacrifice his life in order to safeguard his faith. The concept of Kiddush Hashem is parallel to martyrdom in Christianity and Islam. In its various incarnations over the course of Jewish history, the term Kiddush Hashem gained new meanings. In recent generations, the term has also been applied to Jews who were killed for their national affiliation and not for their beliefs, such as those who died in the Holocaust or in the wars of the State of Israel.
Readiness to die for Kiddush Hashem is already mentioned in the Bible: in Daniel 3:16, Mishael, Azariah, and Hananiah inform Nebuchadnezzar that they are prepared to forfeit their lives so as not to break the commandments of the Torah. When the the Babylonian ruler saw that they refused to breach the prohibition against Idolotry, he had them thrown into a burning furnace, and it was only a miracle that saved them. According to Jewish legend, Abraham was thrown into a fiery oven for refusing to believe in the gods of Ur but was also saved by a miracle  
In the Hellenistic period
And the king sent letters by messengers to Jerusalem and the cities of Judah; he directed them to follow customs strange to the land, to forbid burnt offerings and sacrifices and drink offerings in the sanctuary, to profane sabbaths and feasts, to defile the sanctuary and the priests, to build altars and sacred precincts and shrines for idols, to sacrifice swine and unclean animals, and to leave their sons uncircumcised. They were to make themselves abominable by everything unclean and profane, so that they should forget the law and change all the ordinances. "And whoever does not obey the command of the king shall die."
On the 25th of Kislev, a statue of Zeus was placed in the Holy Temple and sacrifices were offered to it. The death penalty was imposed on any Jew caught circumcising his son or keeping the Sabbath. The authorities forced the Jews to worship idols and offer them sacrifices, and to eat pigs, which are unkosher animals. The decrees of Antiochus lasted three and a half years. Most of Judea's residents chose to die rather than commit idolotry or violate the laws of the Torah. Eleazar the Elder, a prominent dignitary, was ordered to eat from the flesh of a pig and was put to death for his refusal.
One of the most well-known of Kiddush Hashem stories from that time is the story of Hannah and her seven sons. The story relates that Hannah's seven sons were held by the king and commanded to commit idolotry. Each of the sons vehemently refused, including the youngest. The sons were tortured to death, but did not betray their faith. The woman, who lost all her sons, killed herself. The story is described in 2 Maccabees 7:
It happened also that seven brothers and their mother were arrested and were being compelled by the king, under torture with whips and cords, to partake of unlawful swine's flesh. One of them, acting as their spokesman, said, "What do you intend to ask and learn from us? For we are ready to die rather than transgress the laws of our fathers."
In the Roman period
In the year 39 CE, the Roman emperor Caligula instructed that a statue in his image be erected in every temple of the Empire. The Jews refused to place a graven image in the Holy Temple. In response, Caligula ordered this be done by force and, if the Jews object, that the rebels be killed and the whole nation sold into slavery. The Jews declared that they would rather die than transgress the laws of the Torah. Caligula's assassination in