Sixth Sikh Guru
The sixth Guru was the only son of Guru Arjan. His name was Har Gobind. He was only eleven years old when his father was martyred and he became Guru under instructions left by Guru Arjan. Guru Har Gobind wore two swords along with his prayer beads, one represented spiritual power and the other worldly power: these have become part of the symbol of the Sikh faith. (Both of the swords can be seen at the Golden Temple in Amritsar.)
He built the Akal Takht at Amritsar as the seat of authority for the Sikh nation and created the Nishan Sahib (Sikh national flag) which can be seen outside every gurdwara round the world. Guru Har Gobind trained Sikhs to be ready to defend themselves and, more importantly, to defend the weak and oppressed in society whenever necessary. He kept a small army of Sikh warriors.
The Emperor had killed millions of people in his campaign to convert the whole country to Islam and the fifth Guru had already shown that peaceful means could not stop this tyranny. With his massive army and resources, the Emperor attacked the Sikhs on four separate occasions. Guru Har Gobind's small army won every battle. The Guru only fought in self defence or in the defence of innocent people. His victorious army chose to never take land, wealth or possessions after victory. Guru Har Gobind taught that a follower of God cannot stand by and do nothing when their fellow human beings are being oppressed and tyrannised. If all peaceful means to end the tyranny fail then it is right and just to resort to the sword.