The Anglo-Saxon poetical forms are difficult at first to understand. The principal rule of the verse is indeed easy enough; it is the same as in the verse of Piers Plowman; there is a long line divided in the middle; in each line there are four strong syllables; the first three of these are generally made alliterative; i.e. they begin with the same consonant—
Wæs se grimma gæst Grendel haten
mære mearcstapa, se the móras heold
fen and fæsten.
Was the grievous guest Grendel namèd
mighty mark-stalker, and the moors his home
fen and fastness.
or they all begin with different vowels—
Eotenas and ylfe and orcneas.
Etins and elves and ogres too.