Isaac Newton By Sturis Anthony 1666 Isaac Newton found problems in the discovery of calculus in October 1666. Period: 1666 to 1709 Isaac Newton 1667 Isaac Newton returned to Trinity College in 1667 where continued his research in optics. 1667 In 1667 Isaac Newton entered a stage called Annus mirabilis which he made experiments in mathematics and optics 1669 After his research, he constructed the first-ever reflecting telescope in 1669. 1669 Also in 1669, he extended more work in the calculus. 1670 Isaac Newton converted his lectures in 1670-1672 from geometry to where he was concerned more, which was in optics. 1672 In 1672, Isaac went public with his information in optics. 1709 In 1709, Isaac’s colleagues weren’t comfortable with the current Principia and started to argue creating an epic dispute. 1709 During the argument in 1709, Isaac Newton’s theory of gravity provided a rationale so it was more sought out for the new version of the Principia.