In Old English poetry the refrain is used in one poem only, viz. in _Deor's Complaint_, as the repetition of a whole line. In Middle and Modern English poetry the refrain is much more extensively employed. Its simplest form, consisting of the repetition of certain exclamations or single words after each stanza, occurs pretty often in Middle English. Frequent use is also made of the other form, in which one line is partially or entirely repeated. Sometimes, indeed, two or even more lines are repeated, or a whole stanza is added as refrain to each of the main stanzas, and is then placed at the beginning of the poem (cf. Wright's _Spec. of Lyr. Poetry_, p. 51). In English the refrain is also called _burthen_, and consists (according to Guest) of the entire or at least partial repetition of the same words. Distinct from the burthen or refrain is the _wheel_, which is only the repetition of the same rhythm as an addition to a stanza. In Middle English poetry especially a favourite form was that in which a stanza consisting mostly of alliterative-rhyming verses or half-verses (cf. §§ 60, 61, 66) is followed by an addition (the _cauda_), differing very much from the rhythmical structure of the main part (the _frons_) of the stanza, and connected with it by means of a very short verse consisting of only one arsis and the syllable or syllables forming the thesis. This short verse is called by Guest _bob-verse_, and the _cauda_, connected with the chief stanza by means of such a verse, he calls _bob-wheel_, so that the whole stanza, which is of a very remarkable form, might be called the _bob-wheel stanza_. The similar form of stanza, also very common, where the chief part of the stanza is connected with the 'cauda', not by a 'bob-verse' but by an ordinary long line, might be called the _wheel-stanza_. These remarks now bring us to other considerations of importance with regard to the formation of the stanza, which will be treated of in the next section. § =223. The structure and arrangement of the different parts of the stanza= in Middle English poetry were also modelled on Low Latin and especially on Romanic forms. The theory of the structure of stanzas in Provençal and Italian is given along with much interesting matter in Dante's treatise _De vulgari eloquentia_[186], where the original Romanic technical terms are found. Several terms used in this book have also been taken from German metrics.