The office hymn for the Epiphany and its Octave  ‘Hostis Herodes impie’ (translated in the Hymnal as ‘When Christ’s appearing was made known’   and the hymn for Christmastide  ‘A solis ortus cardine’ (‘From east to west  from shore to shore’ ) are parts of a long abecedarian poem on the life of Christ by Caelius Sedulius  a late-classical Christian poet