Pope Leo VIII, Epistola Ad Rodoaldum Patriarcham Aquileiensem, 963 A.D.: “Leo, bishop, servant of the servants of God… If pastors of sheep are content to bear day and night the sun and frost for their care of the flock, and to the end that none of them should either perish wandering, or be snatched by wild beasts, torn by bites, are looking about by ever vigilant eyes, by how much sweat, us, and by how much care must we be completely vigilant, who are called shepherds [pastors] of souls.” (My translation of Migne’s Latin)