It still, however, remains a problem exactly why this particular metre should, as a matter of direct literary imitation, have commended itself so widely to the northern nations. They had nearly or quite as many examples in the same class of the trochaic dimeter
Gaude, plaude, Magdalena
and they paid no attention to this, though their southern neighbours did. They had, from the time of Pope Damasus[163] downwards, and in almost all the hymn-writers, mixed dactylic metres to choose from; but for a staple they went to this. It seems impossible that there should not have been some additional and natural reasons for the adoption—reasons which, if they had not actually brought it about without any literary patterns at all, directed poets to those patterns irresistibly. Nor, as it seems to the present writer, is it at all difficult to discover, as far at least as English is concerned, what these reasons were.
The discovery might be made "out of one's own head"; but here as elsewhere Layamon is a most important assistant and safeguard. A mere glance at any edition of alliterative verse, printed in half lines, will show that it has a rough resemblance on the page to octosyllabics, though the outline is more irregular. A moderately careful study of Layamon shows, as has been indicated, that, in writing this verse with new influences at work upon him, he substitutes octosyllabic couplet for it constantly. And the history in the same way shows that this occasional substitution became a habitual one with others. Not that there is any mystical virtue in four feet, despite their frequency in the actual creation: but that, as an equivalent of the old half line, the choice lies practically between three and four. Now a three-foot line, though actually tried as in the Bestiary and in parts of Horn, is, as a general norm, too short, is ineffective and jingly, brings the rhyme too quick, and hampers the exhibition of the sense by a too staccato and piecemeal presentment. The abundant adoption of the octosyllable in French no doubt assisted the spread in English. But it is not unimportant to observe that English translators and adapters of French octosyllabic poems by no means always preserve the metre, and that English octosyllables often represent French poems which are differently metred in the original.
IV. Decasyllable.—A connected literary origin for this great line—the ancient staple of French poetry, the modern staple of English, and (in still greater modernity) of German to some extent, as well as (with the extension of one syllable necessitated by the prevailing rhythm of the language) of Italian throughout its history—has always been found extraordinarily difficult to assign. That some have even been driven to the line which furnishes the opening couplet of the Alcaic
Quam si clientum longa negotia,
or
Vides ut alta stet nive candidum,
an invariably hendecasyllabic line of the most opposite rhythm, constitution, and division, will show the straits which must have oppressed them. The fact is that there is nothing, either in Greek or Latin prosody, in the least resembling it or suggestive of it. To connect it with these prosodies at all reasonably, it would be necessary to content ourselves with the supposition, not illogical or impossible, but not very explanatory, that somebody found the iambic dimeter too short, and the iambic trimeter too long, and split the difference.
In another way, and abandoning the attempt to find parents or sponsors in antiquity for this remarkable foundling, a not wholly dissimilar conjecture becomes really illuminative—that the line of ten syllables (or eleven with "weak ending") proved itself the most useful in the modern languages. As a matter of fact it appears in the very earliest French poem we possess—the tenth- or perhaps even ninth-century Hymn of St. Eulalia: