Answer:
I presume the answer is Aristotle.
Solved way:
Like many important documents in the history of philosophy and literary theory, Aristotle's Poetics, composed around 330 BCE, was most likely preserved in the form of students' lecture notes.
Furthermore, when searched online, Aristotle is found to be the ‘big three’ poetic as you have asked in your question.
I am not 100% sure if this is correct, and in advance if it is not I’m sorry because this is my best guess and what the answer may be