Him being a <u>cowherd</u> is unusual but significant about Caedmon.
Explanation:
As Bede, the writer, was a devout Christian, he used many references to Christianity in his work. Jesus Christ was considered a shepherd to his flock as he led people out of sinful lives into sin-free lives. Similarly, Caedmon is said to have led people away from their vices and toward the path to heaven through his song. A cowherd was also a person at the bottom of the social ladder. This fact might be meant to imply that through divine grace, even a man from a humble background may change many lives.
The poem has passed down from a Latin translation by Bede in his Ecclesiastical History of the English People. It forms a prominent landmark and reference point for the study of Old English prosody, for the early influence which Christianity had on the poems and songs of the Anglo-Saxon people after their conversion.
The correct answer should be journalists and articles from esteemed sources such as the NY Times in the US, or The Guardian in Britain. You would be advised to not look into yellow pages or other controversial sources.