"It was casted on Erin" is not good English usage. It should be "It was cast on Erin". The base form is "To be cast" referring to a spell which is not the same as "To cast" which refers to someone or something casting a spell. "To be cast" becomes "was cast" in the past.
Even in the case of "He/she/it cast" you would avoid using "casted" as it sounds awful. But, since English is designed to send people who don't have it as their native language crazy, "It was looted" sounds fine and you can it.
Good effort on translation tho, it isn't easy dealing with a language that is a shambling abomination that combines Old German with Old French along with a dash of Greek, Latin and various other languages.