Guru Nanak, the founder of Sikhism, was born in a critical period of Indian history. On one hand, people were divided into castes, sects and factions; on the other, the Musilm rulers perpetrated atrocities on Hindus and the weaker sections of society. The masses in their hardships and miseries, cried for a saviour. Nanak came as God's messenger in the common man's hour of dire need. His followers, called 'Sikhs', formed a group of God-fearing men and women devoted to the service of the people. His life is an inspiring example of the practice of truth, love and humility. Guru Tegh Bahadur carried the conviction - more than four hundred years ago, when religious intolerance and persecution were common all over the world - that every individual must have the freedom to worship the faith of his or her choice. When Aurangzeb began to persecute Hindus ruthlessly, Guru Tegh Bahadur wrote to the emperor, reminding him that the Holy Koran does not sanction forcible conbersion. Great ingenuity was used in devising new kinds of torture for the Guru and his closest disciples, but Aurangzeb failed to crush their spirit. Thus, the Guru laid down his life for a great principle. Even to this day, he is remembered as Hind-di-chadar, protector of India's honour. Guru Gobind Singh was the last of the ten Sikh gurus. His chief contribution was to convert a pacifist, passive and fatalistic community of Punjabi Sikh into a militant, aggressive and determined brotherhood of the Khalsa. It was he who gave Sikhism its five sacred symbols, including the unshorn hair and beard, and who made the Sikhs members of one casteless family - the Singhs.