His first great work of the 'historical' school, and one of his very best, 'The Assassination of James I. of Scotland,' was produced in 1786; as to which a writer in the _Quarterly Review_ for 1866 tells the following amusing story of Northcote's jealousy of Opie. When the latter was engaged at Hampstead on this picture (the story is, by the way, also told of the Rizzio picture), Northcote became alarmed at the reports which reached him of its extraordinary merit, and accordingly he paid a visit to Opie's studio in order to judge for himself. 'When I entered the room,' he said, 'I was astounded. The picture had the finest effect I ever witnessed; the light on the figures gleamed up from a trap-door by which the murderers were entering the King's chamber. "Oh!" said I to myself; "go home, go home; it is all over with you!" I did go home, and brooded over what I had seen. I could think of nothing else; it perfectly haunted me. I could not work on my own pictures for thinking of his. At last, unable to bear it any longer, I determined to go there again, and when I entered the room I saw, to my great comfort, that Opie had rubbed all the fine effect out.' In the following year his next great work, 'The Assassination of David Rizzio,'[118] was painted, and Opie's claim to be elected an Associate of the Royal Academy was established, the full honours being accorded to him the year after. His diploma picture, 'Age and Infancy,' still hangs on the Academy's walls. Amongst his other more important works may be named, 'The Presentation in the Temple,' 'Jephthah's Vow,' 'Young Arthur taken Prisoner,' 'Arthur with Hubert,' 'Belisarius,' 'Juliet in the Garden,' 'The Escape of Gil Blas' (his last historical work), and 'Musidora.' A very large proportion of these, and others of Opie's paintings have been engraved. It may be here mentioned, as an illustration of the prices which some of Opie's best works fetch, that at the sale of Mr. Jesse Watts Russell's pictures, at Christie and Manson's, in July, 1875, 'The Schoolmistress,' from the collection of Mr. Watson Taylor, a large and important work of several figures--an old lady schoolmistress and her pupils--painted in emulation of Rembrandt, fetched £787 10s. Pursuing his career at the Royal Academy, in 1789, on the expulsion of Barry, the Professor of Painting, on account of his impertinent remarks upon his brother Academicians, and his generally unsatisfactory conduct, Opie preferred his claims; but was induced to waive them in favour of the elder artist, Fuseli. The latter, however, resigned in 1805, and the indisputable claims of Opie to the post were at once fully and honourably recognised.