Guru Nanak, the first of the 10 Gurus, founded the Sikh religion. He was born in 1469 AD at a time when there was a great deal of corruption in Indian society.
The rich and powerful rulers were misruling and oppressing the helpless poor people, offering them no justice and having no sympathy for them. Guru Nanak spoke out against the tyrannical rulers and forced them to change their ways. He believed in the rights and freedom of the people and opposed rulers and their empires. He was not against any particular people but only what they stood for if it was wrong.
Guru Nanak believed in one God, one brotherhood and universal love.
The message of Guru Nanak was devotion to God, and love amongst humanity. This message was carried forward and developed by each of the 10 Gurus who followed after him.