tia quoniam est, [Greek: ousiosis] uero atque subsistentia
quoniam in nullo subiecto est, [Greek: hupostasis] uero atque substantia,
quoniam subest ceteris quae subsistentiae non sunt, id est [Greek:
ousioseis]; est [Greek: prosopon] atque persona, quoniam est rationabile
indiuiduum. Deus quoque et [Greek: ousia] est et essentia, est enim et
maxime ipse est a quo omnium esse proficiscitur. Est [Greek: ousiosis], id
est subsistentia (subsistit enim nullo indigens), et [Greek:
huphistasthai]; substat enim. Vnde etiam dicimus unam esse [Greek: ousian]
uel [Greek: ousiosin], id est essentiam uel subsistentiam deitatis, sed
tres [Greek: hupostaseis], id est tres substantias. Et quidem secundum hunc
modum dixere unam trinitatis essentiam, tres substantias tresque personas.
Nisi enim tres in deo substantias ecclesiasticus loquendi usus excluderet,
uideretur idcirco de deo dici substantia, non quod ipse ceteris rebus quasi
subiectum supponeretur, sed quod idem omnibus uti praeesset ita etiam quasi
principium subesset rebus, dum eis omnibus [Greek: ousiosthai] uel
subsistere subministrat.

[59] quas illi _Vallinus_; quasi _uel_ quas _codd. meliores_.

III.

Wherefore if Person belongs to substances alone, and these rational, and
if every nature is a substance, existing not in universals but in
individuals, we have found the definition of Person, viz.: "The
individual substance of a rational nature."[60] Now by this definition
we Latins have described what the Greeks call [Greek: hupostasis]. For
the word person seems to be borrowed from a different source, namely
from the masks which in comedies and tragedies used to signify the
different subjects of representation. Now _persona_ "mask" is
derived from _personare_, with a circumflex on the penultimate. But
if the accent is put on the antepenultimate[61] the word will clearly be
seen to come from _sonus_ "sound," and for this reason, that the
hollow mask necessarily produces a larger sound. The Greeks, too, call
these masks [Greek: prosopa] from the fact that they are placed over the
face and conceal the countenance from the spectator: [Greek: para tou
pros tous opas tithesthai]. But since, as we have said, it was by the
masks they put on that actors played the different characters
represented in a tragedy or comedy--Hecuba or Medea or Simon or
Chremes,--so also all other men who could be recognized by their several
characteristic