No Wandering Monks

Letter 1,40 - to sub-deacon Anthelm. April 591.

"(S)ome monks from monasteries located in the diocese of Sorrento are changing their abodes from monastery to monastery. With the desire for secular things, they are abandoning the rule of their own abbot. Moreover, individuals are applying themselves to their personal gain, which is known to be illegal.
For that reason we command your Experience with the present order not to allow any monk to move his abode from monastery to monastery any further, nor to permit any one of them to have any personal interests.
But if anyone should presume upon this, he must be returned with due coercion to the monastery where he became a monk, and back under his abbot's rule, from which he fled. Otherwise, if we leave such great sin uncontrolled and unamended, the souls of those perishing may be examined by the soul of their superiors (..). For in this way you will please the eyes of God and will be found participant in full recompense."

Cited from: The Letters of Gregory the Great, trans. John R.C. Martyn (Toronto: PIMS, 2004), I: 121.