The best known disciple of Máel Ruain's community was Óengus the Culdee, the author of the "Félire Óengusso", a versified martyrology or calendar commemorating the feasts of Irish and non-Irish saints, and possibly also of the earlier prose version, the "Martyrology of Tallaght". In his epilogue to the "Félire Óengusso", written sometime after Máel Ruain's death, Óengus shows himself much indebted to his "tutor" ("aite"), whom he remembers elsewhere as "the great sun on Meath's south plain" ("grían már desmaig Midi"). In the early ninth century, Tallaght also seems to have produced the so-called "Old Irish Penitential".