To Eustathius bishop of Sebastia. cf. Letter cxix.  Sebaste is Siwas on the Halys.  On Eustathius to Basil a type at once of the unwashable Ethiopian for persistent heresy (Letter cxxx. 1) and of the wind-driven cloud for shiftiness and time-serving, (Letter ccxliv. 9.)  Vide proleg.