Just as rhyme was seen in some Anglo-Saxon poems (e.g. "The Rhyming Poem", and, to some degree, "The Proverbs of Alfred"), the use of alliterative verse continued into Middle English. Layamon's "Brut", written in about 1215, uses a loose alliterative scheme. Starting in the mid-14th century, alliterative verse became popular in the English North, the West Midlands, and a little later in Scotland. The Pearl Poet uses a complex scheme of alliteration, rhyme, and iambic metre in his "Pearl"; a more conventional alliterative metre in "Cleanness" and "Patience", and alliterative verse alternating with rhymed quatrains in "Sir Gawain and the Green Knight". William Langland's "Piers Plowman" is an important English alliterative poem; it was written between "c". 1370 and 1390. The form of alliterative verse changed gradually over time. From "Piers Plowman":