I am always afraid these questions will seem like I'm trying to pick a fight. I'm not. I am discerning where I should be. I am considering Orthodoxy, and admittedly am in the "crush" stage of the relationship. That said, 50 years of being a Catholic who did the homework is a constant issue for me. so I keep doing research to see where the whole Church started and how it developed or split to get where it is today.
In 450-ish AD Orthodoxy split into Chalcedonian Orthodox (Eastern) and non-Chalcedonian (Oriental orthodox.)
If Catholicism was always the mainline Christianity from which Orthodoxy split, Why wouldn't the oriental Orthodox be "Oriental Catholic?" Was there already a delineation between Catholicism and Orthodoxy in 450AD?
I don't know if this makes sense, but If Eastern Orthodoxy didn't exist until 1054, how could Oriental Orthodoxy have split from it so early on?