Bertrand Arthur William Russell,18 May 1872–2 February 1970) was a British philosopher, logician, mathematician, historian, writer, social critic and political activist. At various points in his life he considered himself a liberal, a socialist, and a pacifist. In the early 20th century, Russell led the British "revolt against idealism".He is considered one of the founders of analytic philosophy along with his predecessor Gottlob Frege, colleague G. E. Moore, and his protégé Ludwig Wittgenstein. He is widely held to be one of the 20th century's premier logicians. With A. N. Whitehead he wrote Principia Mathematica, an attempt to create a logical basis for mathematics.