Martyrdom in Sikhism

Martyrdom is a fundamental institution of Sikhism. Sikh festivals are largely focused on the lives of the Sikh gurus and Sikh martyrs. Their martyrdoms are regarded as instructional ideals for Sikhs, and have greatly influenced Sikh culture and practices. The Fifth Guru, Guru Arjan Dev, is generally regarded as the first Sikh martyr.
Martyrdom.
Martyrdom is a fundamental institution of the Sikh faith. When one calls an individual a "shahid", this connotes more than its definition in Arabic vocabulary or Islamic faith, which is death in battle with the infidels. For the Sikh, the perfect martyr or "shahid" is one who died not just in battle but also one who suffered death by refusing to renounce his faith, tenets and principles. The Sikh experience through the years gave rise to this type of ideal martyrdom.
Bhai Taru Popat was the first Sikh at the time of Guru Nanak Dev (1469-1539). Bhai spoke against Babur, the Mughal emperor and he was set on fire by soldiers of Babur. The martyrdom of Guru Arjan in the 17th century is regarded as a key moment in Sikh tradition which has influenced Sikh practices and beliefs, helping define a deliberately-separate and militant Sikh community.
The later martyrdom of Guru Tegh Bahadur, who refused to convert to Islam in an effort to protect Hindu religious practice, is credited with making respect for freedom of conscience a key part of Sikh identity. The emperor tried to convert Guru Teg Bahadur to Islam hoping that it would be easier to convert his followers if he relented. The guru was executed because he refused. Experts stated that these events galvanized the concept of Sikh martyrdom in the sense that Guru Arjan's death brought the Sikh Panth together while Guru Teg Bahadur's execution finally gave Sikh martydom its identity. Guru Teg Bahadur's death provided the impetus for his son, the tenth Guru Gobind Singh, to impose an outward form of Sikh identity as well as pride in his father's martyrdom. To avoid fear and demoralization, he instituted a new Sikh order called Khalsa founded on discipline and loyalty, and martyrdom became one of its foundations. Succeeding Gurus built on this new orientation, establishing a strong, self-governing warrior group.
Reference.
https://en.wikipedia.org/wiki/Moti_Ram_Mehra