This Thursday is feast of Corpus Christi. It is a beautiful Mass composed by St. Thomas Aquinas, in the wake of the heresy of Berengarius, who lived in the eleventh century (it is remarkable that the Holy Eucharist went a thousand years without a serious heresy threatening it directly, and no less so that the error of Berengarius, nearly alone among heresies, found almost no traction among the men of his age!). The faithful reacted vigorously in defense of the Blessed Sacrament which they loved; this era saw the advent not only of the feast of Corpus Christi, but also the major elevations at Mass (at the consecration), Eucharistic processions, and other pious acts of devotion towards Our Lord present in the Most Holy Eucharist.