I'm a beginner in Japanese; and as an exercise I've tried to translate a sentence from the LN. While I do realize that I've bit more that I can chew, I wish to at least try :)
The sentence that I am struggling with is (with emboldened specific point)
その中で放たれた時空の大魔法は、日本のとある高校の教室で炸裂した。
As far as I can tell, emboldened part means (roughly) 'was released in space-time/exploded space time'. I don't really understand the たれた suffix. We have 放 in past tense, TA form used to modify 時空. I would expect this word to have った suffix. What am I missing?