Besides being a contributor to the magazines and encyclopedias on educational and philosophical subjects, he wrote An Introduction to the Study of Philosophy (1889); The Spiritual Sense of Dante's Divina Commedia (1889); Hegel's Logic (1890); and Psychologic Foundations of Education (1898); and edited Appleton's International Education Series and 'Webster's International Dictionary.
By far the greatest disciple of Aquinas is Dante Alighieri, in whose Divina Commedia the theology and philosophy of the middle ages, as fixed by Saint Thomas, have received the immortality which poetry alone can bestow.
"In a language which is singularly poor in mystical works it stands with the Divina Commedia as one cf the two supreme attempts to express the eternal in the symbolism of a day, to paint the union of the soul with the supra-sensible while still imprisoned in the flesh."
The public was at first greatly mystified by the nature and object of this poem, which was not merely a chronicle of Tennyson's emotions under bereavement, nor even a statement of his philosophical and religious beliefs, but, as he long afterwards explained, a sort of Divina Commedia, ending with happiness in the marriage of his youngest sister, Cecilia Lushington.
There remains a short piece without title, the Commedia in prosa, which, if it be Machiavelli's, as internal evidence of style sufficiently argues, might be accepted as a study for both the Clizia and the Mandragola.
Plumptre was a man of great versatility and attained high reputation as a translator of the plays of Sophocles (1865) and Aeschylus (1868), and of the Divin g commedia of Dante (1886).
The compositions belonging to the period of his residence at Weimar comprise two pianoforte concertos, in E flat and in A, the " Todtentanz," the " Concerto pathetique " for two pianos, the solo sonata " An Robert Schumann," sundry " Etudes," fifteen " Rhapsodies Hongroises," twelve orchestral " Poemes symphoniques, " " Eine Faust Symphonie," and " Eine Symphonie zu Dante's ` Divina Commedia,' " the " 13th Psalm " for tenor solo, chorus and orchestra, the choruses to Herder's dramatic scenes " Prometheus," and the " Missa solennis " known as the " Graner Fest' Messe."
Once more the poet sought refuge in medieval life by completing his translation of the Divina Commedia, parts of which he had rendered into English as much as thirty years before.