Who is Socrates from The Story of Philosophy and what is their importance?

Socrates is born in 469 B.C. and lives until 399 B.C. He drinks poisonous hemlock at the age of seventy in 399 B.C. Critias is the uncle of Plato and studies under Socrates. Like his pupil Critias, Socrates is an aristocrat. He is considered the intellectual leader of the rich man's revolution against democracy. He is a bald, large, round-faced homely man with deep-set staring eyes and a broad nose. Socrates has an ungainly walk and wearing a rumpled tunic makes it more obvious. He neglects his children and wife.