1.

I must express my satisfaction, and congratulations, and admiration, my son Boniface, ¹ in that, amid all the cares of wars and arms, you are eagerly anxious to know concerning the things that are of God. From hence it is clear that in you it is actually a part of your military valor to serve in truth the faith which is in Christ. To place, therefore, briefly before your Grace the difference between the errors of the Arians and the Donatists, the Arians say that the Father, the Son, and the Holy Ghost are different in substance; whereas the Donatists do not say this, but acknowledge the unity of substance in the Trinity. And if some even of them have said that the Son was inferior to the Father, yet they have not denied that He is of the same substance; whilst the greater part of them declare that they hold entirely the same belief regarding the Father and the Son and the Holy Ghost as is held by the Catholic Church. Nor is this the actual question in dispute with them; but they carry on their unhappy strife solely on the question of communion, and in the perversity of their error maintain rebellious hostility against the unity of Christ. But sometimes, as we have heard, some of them, wishing to conciliate the Goths, since they see that they are not without a certain amount of power, profess to entertain the same belief as they. But they are refuted by the authority of their own leaders; for Donatus himself, of whose party they boast themselves to be, is never said to have held this belief.