Rhyme royal

Rhyme royal is a seven-line stanza with rhyme scheme a-b-a-b-b-c-c. It is also spelled Rime royal.
It is unknown who invented this scheme. Geoffrey Chaucer introduced the stanza into English poetry in 14th century. It may have been borrowed from Italian or French poetry, but the form became typically English. Chaucer used the form in "Troilus and Criseyde". Rhyme royal was popular in the 15th and 16th centuries.
Many English and Scottish poets used rhyme royal. It is suitable for long poems. In English literature rhyme royal is almost always composed of ten-syllable lines with five beats. Outside England rhyme royal is not as popular. In the United States Emma Lazarus wrote some poems using ababbcc rhyme-scheme. This stanza comes form her poem "Sympathy" (included in "Epochs").
Poets who wrote rhyme royal frequently were William Morris and John Masefield. In 20th century the stanza went out of use.