What was Auguste Comte best known for that relates to sociology?

Auguste Comte was, in some ways, the founder of the whole
discipline of sociology.  It was he who made up the term "sociology" and it was he who
pioneered what he saw as the objective study of
society.

Comte felt that people who had studied society
before him had generally done so from a critical point of view.  They had been more
interested in criticizing society than in studying it.  Because of this, he became
interested in studying the whole of society and in figuring out the functions of various
aspects of society that other people thought were simply bad.  He tried to explain how
those aspects of society functioned as part of the whole rather than simply arguing that
those aspects were dysfunctional.  In doing so, he helped to start a new discipline in
which scholars tried to study society in an objective
way.

Comte, then, is best known for being one of the
fathers of modern sociology.