Alliteration and double rhyme are two main poetic means commonly used in old English poetry.
Alliteration refers to a rhetorical device of repeating the same consonant phoneme in poetry or prose, which originated from the main prosodic form of ancient western European poetry.
Double rhyme style is a kind of English classical poetry style, which evolved from ten-syllable double rhyme style. There are five steps in each line, and each step has two syllables, the first is light tone, and the second is stress.