Cecilia McDowall O Antiphon Sequence, For Solo organ. O Antiphon Sequence was conceived as a recital piece, although each of its individual movements would also work in a liturgical context. Each movement is a response to a short extract of liturgical text taken from the 'O Antiphons', which are the Magnificat antiphons used at Vespers during the last seven days of Advent in Western Christian traditions. The work was commissioned by the American Guild of Organists for performance at the 2018 AGO.