There is no clear evidence before 1859 of an intention to treat the Arthurian story as a whole. In that year four of the idylls were published; but they were still fragments, and great gaps were left between. Gradually the gaps were filled, until in 1885 the poem was completed. Still, the connexion of the parts is loose. Each idyll is a separate story, related to the others because all are parts of one greater story. But the idylls have not the coherence required in the books of an epic. Tennyson was conscious of the want of unity, and he sought for a principle of connexion in allegory. At best the allegory is very indistinct; it appears chiefly in the parts later in order of publication; and we may suspect that it was an after-thought meant to supply a defect to which the author slowly awakened. The very name, _Idylls of the King_, serves as a warning not to expect too much unity. An 'idyll' is a short story, and the word therefore indicates the essentially episodic character of the whole poem. The _Idylls_ were, as they still are, Tennyson's greatest experiment in blank verse; and next to Milton's _Paradise Lost_ they are the finest body of non-dramatic blank verse in the language. The form had gone out of fashion in the eighteenth century. Thomson, it is true, revived it, and the poets of the period of the Revolution followed his example. But through the early death of Keats, through that feebleness of will which robbed the world of an untold wealth of poetry in Coleridge, and through the fate that forbade Wordsworth to write long poems well, it remained true that no very great and sustained modern English poem was written in blank verse. The measure attracted Tennyson, and he soon mastered it. A number of pieces prior to the _Idylls_ seem to be experiments in preparation for a bolder flight. The _English Idylls_, _Ulysses_, _Aylmer's Field_, _Sea Dreams_ and _Lucretius_ are specimens. The measure is used on a larger scale in _The Princess_. But Tennyson's supreme success was in the _Idylls of the King_. They cannot be said to rise higher than the best of the early poems; for the _English Idylls_ include the _Morte d'Arthur_, and _Ulysses_ is among the finest of Tennyson's poems. These pieces show the same exquisite grace, the same smoothness, the same variety of pause, the same skill in the use of adjuncts, such as alliteration. But there is necessarily more scope and variety in a long poem; and one of the finest features of Tennyson's verse is the flexibility with which it adapts itself to the soft idyllic tone appropriate to _Enid_, to the darkness of moral degradation in _The Last Tournament_, to the crisis of the parting of Arthur and Guinevere, to the spiritual rapture of _The Holy Grail_, and to the mysticism of _The Passing of Arthur_. Tennyson cannot equal the stateliness of Milton; but Milton is the only poet with whom, in respect of blank verse, he need greatly fear comparison.