The story of the four novices (sāmaṇera): Saṅkicca, Paṇḍita, Sopāka, and Revata.
See Pañcacchiddageha. Ñāṇābhivaṃsa (see below) wrote a fresh account of the story.
A compilation by Ñāṇābhivaṃsa Saṅgharāja. Bode, op.cit., 78. For the story see DhA.iv.176 f.