5 I implore your blessedness, therefore, by the crucified Saviour of the world, and by the consubstantial trinity, to authorize me by letter either to use or to refuse this formula of three hypostases. And lest the obscurity of my present abode may baffle the bearers of your letter, I pray you to address it to Evagrius, the presbyter, with whom you are well acquainted. I beg you also to signify with whom I am to communicate at Antioch. Not, I hope, with the Campenses; for they— with their allies the heretics of Tarsus — only desire communion with you to preach with greater authority their traditional doctrine of three hypostases.
Source: Letters (New Advent)