Why does it say AOI at the end of stanzas(? i dont know if thats what they are called) in The Song of Roland?

Question

i am reading this for my Heroes and Villains class and i dont know what AOI means :
1
Charles the king, our mighty emperor,
has been in Spain for all of seven years,
has won that haughty land down to the sea.
There is no castle still opposing him,
nor town or wall remaining to be be crushed,
except the mountain city, Saragossa.
Marsilla holds it; he does not love God,
but serves Mohammed and invokes Apollo.
No matter what he does, his ruin wil come. AOI

it comes up very often too and i really dont know what it stands for. any insight would be VERY helpful!

Answer 1

"A number of laisses end with the letters AOI. No one knows what they mean, although they may be either some kind of musical indication or an abbreviated prayer. They do seem to occur at important moments in the poem."

"Their poetic meter or measured line helped the poet remember how the next part of the text was to go. In the Chanson de Roland the AOI that ends many laisses or stanzas may be a refrain the jongleur both sings and strums upon his harp. It may function like punctuation in a written text, giving him time to pause and assemble in his memory the next stanza in the poem. This is poetry to be heard by the physical ear, not seen by the physical eye."

Answer 2

scholars actually aren't sure what it means, they believe it is like an exclamation point