Institutio Oratoria

Quintilian

Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.

The practice of joining e and i as in the Greek diphthong ει lasted longer: it served to distinguish cases and numbers, for which we may compare the instructions of Lucilius:

  1. The boys are come: why then, their names must end
  2. With e and i to make them more than one; and later—
  1. If to a thief and liar ( mendaci furique ) you would give,
  2. In e and i your thief must terminate.
But this addition of e is quite superfluous, since t can be long no less than short: