Karl Marx was born in the German city of Trier in 1818. He studied law in Bonn and Berlin at his father's insistence, but his true interests lay elsewhere and, in 1841, he received a doctorate in philosophy from the University of Jena.

For the next two years he wrote for radical left-wing newspapers before moving to Paris with his wife, Jenny; there he became a communist and met his lifelong friend and collaborator, Friedrich Engels.

They published their revolutionary pamphlet, The Communist Manifesto, in 1848 and Marx moved to London a year later. He spent the rest of his life there - often in considerable poverty - while he wrote his magnum opus of political theory, Das Kapital. Karl Marx died in 1883.

Swami Vivekananda (1863-1902), a Hindu monk, was the foremost disciple of the sage Ramakrishna and a world spokesman for the school of Hindu philosophy called Vedanta.

He founded the Ramakrishna Order in India in 1898 and was responsible for the revival of Hindu spiritualism and established Hinduism as a revered religion on the world stage.