This Sunday, the feast of the Body and Blood of Jesus Christ, is one of the Sundays at which there is a sequence – a chant or hymn that comes before the Gospel. At one point there were sequences every Sunday and holy day; eventually, only five were retained. We have sequences during the octaves of Easter, Pentecost, and Corpus Christi. The sequences for All Soul’s Day and the feast of Our Lady of Sorrows are now more often sung as hymns in the Office. The only obligatory…