The historical story line is based on the Old English epic Beowulf, a poem believed to have been written about 750 AD.
Beowulf is written in 6,359 verses. Each verse has two accented trochee syllables, a pause, and then the second hemistitch of two accented syllables. There is no rhyme, and instead the Beowulf scop (bard) used allliteration, repeating consonant sounds.
If none of that last paragraph meant anything to you, relax. You're normal. Not many people except English professors care about trochees or hemistitches. Here's a brief example, which might help you understand. It is Old English, which is barely recognizable to us, so I've included a translation as well.
(God amidst the Geats Grendle's deeds)
wlanc Weders leod word aefter spraec
(The proud Weder lord Words after spoke)
Beautiful to behold it was, full of fulsome wonder
Heavy the herds on the plains Bounteous the berries beneath the forest
It was beautiful to behold, and full of wonder
Huge herds roamed the plains, berries filled the forest
Sometimes it's good to sacrifice some authenticity for the sake of meaning.