Poems like Piers Plowman don't rhyme. In fact, their metre is fundamentally different from the rhyming iambic pentameter-style metre of Chaucer and his successors. Fortunately, you only need to know TWO principles to understand it!

I say 'principles' rather than 'rules' because many alliterative poets, particularly Langland, could be quite flexible about following these rules.

These tutorials aim to help you get a clear idea of what the basic norms of poems like Piers Plowman and Sir Gawain and the Green Knight are -- and so to spot when the poems do things that are unusual, weird, and special, so that you can comment on these divergences.

Of course, there's a lot more to know about alliterative verse than what you find here: there's loads of fascinating research and debate going on about the precise conventions followed by different poets, at different times. But these pages will give you the fundamentals that will allow you to appreciate and criticise the poetry.