The first effective demonstration of a telescope using reflecting optics was made by Isaac Newton, and his invention was given widespread publicity by the Royal Society of London in 1672. Newtonts instrument was closely associated with the introduction of his new theory of the nature of white light and colour, and for Newton his telescopes practicability remained important to the acceptance of his optical theory. Newtonts telescope, influenced to some extent by the earlier work of James Gregory, encouraged the Royal Society to promote more ambitious trials, but instruments by Robert Hooke and Christopher Cock, and by Newton himself, achieved only limited success. Renewed interest in the reflector followed its re- emergence in Newtonts Opticks of 1704. John Hadleyes successful revival of Newtones instrument led in turn to the establishment in London of competitive commercial manufacture of reflectors in the early 18th century, and by 1710 the market was dominated by the instruments of James Short. Contemporary references to the reflecting telescopes of Newton and others have been analysed to allow the historical development of this work to be established more reliably, and to propose a relationship between the various instruments that may be ascribed to Newton. The emphasis has therefore been placed on the instrumentation itself, on practical detail, and on questions of provenance.