John Toland, an Irishman, one of the earliest and ablest of the new sect of Free-thinkers, made his appearance at Dublin in 1696, as the author of _Christianity not Mysterious_. The book was condemned by College dignitaries and dignified clergy with even more than Irish fervour. It was the opening of a controversy that lasted over half of the eighteenth century in England, in which Berkeley soon became prominent; and it was resumed later on, with greater intellectual force and in finer literary form, by David Hume and Voltaire. The collision with Toland about the time of Berkeley’s matriculation may have awakened his interest. Toland was supposed to teach that matter is eternal, and that motion is its essential property, into which all changes presented in the outer and inner experience of man may at last be resolved. Berkeley’s life was a continual protest against these dogmas. The Provost of Trinity College in 1700 was Dr. Peter Browne, who had already entered the lists against Toland; long after, when Bishop of Cork, he was in controversy with Berkeley about the nature of man’s knowledge of God. The Archbishop of Dublin in the early years of the eighteenth century was William King, still remembered as a philosophical theologian, whose book on the _Origin of Evil_, published in 1702, was criticised by Boyle and Leibniz. Dublin in those years was thus a place in which a studious youth, who had been “distrustful at eight years old,” might be disposed to entertain grave questions about the ultimate meaning of his visible environment, and of the self-conscious life to which he was becoming awake. Is the universe of existence confined to the visible world, and is matter the really active power in existence? Is God the root and centre of all that is real, and if so, what is meant by God? Can God be good if the world is a mixture of good and evil? Questions like these were ready to meet the inquisitive Kilkenny youth in his first years at Dublin. One of his earliest interests at College was mathematical. His first appearance in print was as the anonymous author of two Latin tracts, _Arithmetica_ and _Miscellanea Mathematica_, published in 1707. They are interesting as an index of his intellectual inclination when he was hardly twenty; for he says they were prepared three years before they were given to the world. His disposition to curious questions in geometry and algebra is further shewn in his College _Commonplace Book_.