Now, please explain to me about the Mercian court.
It's just a literary device in my screenplay...a mechanism to get Oswald to leave. His story is that he is a younger son of a Mercian earl in Britain in the latter part of the 8th century. He's brash, smart, hedonistic, a wiseacre, and an utter pain in the neck to responsibile folks...but he's good with weapons. He makes himself unpopular with Offa, king of Mercia, when he's caught in a compromising position with a younger female cousin of the king. To A) preserve Oswald's life, B) discipline the young man, and C) get him out from underfoot, Oswald's father packs him off to a distant island monastery where he won't be able to be much of a nuisance.
That island is Iona, the setting (and title) of my story. Oswald becomes one of several influences on my protagonist.