The Council of Nicaea
The great Synod has stringently forbidden any bishop, presbyter, deacon, or any one of the clergy whatever, to have a subintroducta dwelling with him, except only a mother, or sister, or aunt, or such persons only as are beyond all suspicion.
Source details
A.D. 325 · Canon 3 (325)
Checked word-for-word against Nicene and Post-Nicene Fathers, Series 2, Vol. 14 · 2026-07-26