Johann Caspar Lavater, an eloquent preacher and distinguished theologian, is the once-famous author of Essays on Physiognomy. By 1814, when he described Byron's appearance, Thomas Lawrence, as Borrow after him, had become a confirmed physiognomist, "a kind of Lavater". He observed Byron closely and acutely, and what he saw he interpreted within the context of Lavater's discussion of facial features. Physiognomy was "practiced by Pythagoras, defended by Socrates, approved by Plato, and treated by Aristotle," according to Thomas Cooper, whose learned and thoughtful estimate of Lavater's achievement appeared in 1790. Lavater considered painting "the mother and daughter of physiognomy"; drawing was the physiognomist's natural tool. Thomas Sully came to professional maturity at a time when interest in Lavater's Essays was peaking. Even more than Lawrence, it was the Swiss artist who honed Sully's awareness of physiognomical precepts. By July 1809, when Sully arrived in England, Fuseli had presented before the Royal Academy eight of his 12 Lectures on Painting.