Particular Churches are fully Catholic through their communion with one of them, the Church of Rome "which presides in charity" (315)--
315- St. Ignatius Antioch
"for with this church,by reason of its pre-eminence, the whole Church, that is the faithful everywhere.........blah blah blah..............
I'm not sure how helpful that is.
Don't shoot the messenger!!!!
P.S. I have no idea where St. Ignatius wrote this part of it but ....?