Abu Nasr al-Farabi was an influential 10th century philosopher from Central Asia who made important contributions to the fields of logic, mathematics, music and political philosophy. He believed that philosophy and Islam were compatible and sought to classify all knowledge into different categories and subcategories. In his work "The Book of the Enumeration of Sciences", he divided knowledge into five major chapters covering language, logic, mathematics, physics/metaphysics and political/legal sciences. Within mathematics he included seven subfields. Al-Farabi also wrote extensively on music and invented several musical instruments. He sought to make logic more accessible by dividing it into ideas and proofs.