Isaac Newton was knighted by Queen Anne of England in 1705. By that time, he had already been elected president of the Royal Society. Both of these events evidence how Newton had increasingly been put in the spotlight as a public figure later in his life.
At the time of his knighting, Isaac Newton had essentially given up his career in science to be a politician, and by his death, he was widely known throughout the European continent.
His greatest contribution to science was his theory of gravity. In "Mathematical Principles of Natural Philosophy," Newton describes the force of gravity and how it acts on objects. He also essentially started the field of optics with his work on light.