Which 17th-century German philosopher argued in 'Monadology' that reality consists of simple, indivisible substances called monads?

Gottfried Wilhelm Leibniz

Leibniz proposed that the universe is made of these 'monads,' which are simple, indivisible substances that do not interact with each other physically. He famously argued that we live in the 'best of all possible worlds' because God chose the most harmonious arrangement of these monads.