A little while ago, I finished Before France and Germany by Patrick Geary. From this book I got the impression that the church was comparatively decentralized in the time immediately following the the last Roman emperor: the Pope was "first among equals" of the Bishops, and Bishops were largely independent.
But in particular, it seemed to suggest that the monastic movements that spread into western Europe were initially independent from the bishops (and even clashed with the diocesan church structure), and that they gradually began to fall under episcopal authority through later pressure from the bishopric, and the general trend of increasing organization as the "dark ages" progressed.
However, this wikipedia page outright says that abbots were subject to episcopal jurisdiction right from the beginning, following from the Code of Justinian.
Can someone help me untangle this knot? To what extent were monasteries independent institutions? How did this change over time?
I beleive manastacism developed independently from the bishops and was opposed by the bishops in the ancient world. I recall a prominent Bishop of Alexandria actively opposed or undermined early monastic communities because they were outside his authority. I will see if I can dig it up.