Following his return to Cambridge University in 1667, after the plague epidemic; Isaac Newton became a minor fellow of Trinity College and, furthermore, the next year went on to become a senior fellow of Trinity College subsequent to his being awarded the Master of Arts degree. Soon after, in 1669, when he was 26 years of age, Newton was appointed as Lucasian Professor of Mathematics.
Due to the invention of his scientific telescope, Newton’s abilities were finally brought to the attention of the scientific community and in 1672 he was elected a fellow of the Royal Society.
Soon after his election, Newton published his first paper concerning the nature of colour. This paper proved to be extremely controversial among the other members of the Royal Society and created a series of bitter disputes between Newton and a certain Robert Hooke. Newton retreated after the initial skirmish, only to return again with a second paper, this one to be charged with claims of plagiarism. Consequent to these controversies, Newton suffered a nervous breakdown in 1678, which further escalated after the death of his mother in 1679, resulting in his withdrawal from all forms of contact with others and complete engrossment in his studies.
During this time of isolation, Newton further developed his theories concerning gravitation and planetary motion, which he had begun during the closure of Cambridge due to the Plague. Thus, in 1687, Newton, with the support of his friend Edmond Halley, an astronomer of the time, wrote and published ‘Philosophiae Naturalis Principia Mathematica’, or simply the 'Principia'. This book explained Newton’s theories regarding gravity, as well as his Laws of Motion, and it is believed to be his greatest and most important piece of work. Hooke again claimed that plagiarism had occurred in the making of this book and attempted to gain a position on the receiving end of the recognition that accompanied the publication of the book. This argument was grounded on the fact that Hooke had attempted to contact Newton regarding the question of planetary motion, previous to the development of the book. However this was to no avail, as Newton had cultivated such a deep resentment towards Hooke , remaining withdrawn from the Royal Society until the death of Hooke in 1703.