(i)  Of the works comprised under this head, the first are the three compositions entitled Tractatus Prævii.  The first, Prævia Institutio ascetica (᾽Ασκητικὴ προδιατύπωσις ), is an exhortation to enlistment in the sacred warfare; the second, on renunciation of the world and spiritual perfection, is the Sermo asceticus (λόγος ἀσκητικός).  The third, Sermo de ascetica disciplina (λόγος περὶ ἀσκήσεως, πῶς δει κοσμἑισθαι τὸν μοναχόν), treats of the virtues to be exhibited in the life of the solitary.