The Eucharist in the Lutheran Church (also called the Mass, the Sacrament of the Altar, the Lord's Supper, the Lord's Table, Holy Communion, the Breaking of the Bread, and the Blessed Sacrament) refers to the liturgical commemoration of the Last Supper. Lutherans believe in the real presence of Christ in the Eucharist, affirming the doctrine of sacramental union, "in which the body and blood of Christ are truly and substantially (vere et substantialiter) present, offered, and received with the bread and wine." Beliefs The Eucharist is based on the events of , , , and . Lutherans believe that the Body and Blood of Christ are "truly and substantially present in, with and under the forms" of consecrated bread and wine (the elements), so that communicants eat and drink both the elements and the true Body and Blood of Christ himself in the Sacrament of the Eucharist whether they are believers or unbelievers. The Lutheran doctrine of the Real Presence is also known as the sacramental union. This theology was first formally and publicly confessed in the Wittenberg Concord (1536). It has been called "consubstantiation," but Lutheran theologians reject the use of this term "since Lutherans do not believe either in that local conjunction of two bodies, nor in any commingling of bread and of Christ's body, of wine and of his blood." Lutherans use the term "in, with, and under the forms of consecrated bread and wine" and "sacramental union" to distinguish their understanding of the Eucharist from those of the Reformed and other traditions. Use of the sacrament For Lutherans the Eucharist is not considered to be a valid sacrament unless the elements are used according to Christ's mandate and institution (consecration, distribution, and reception). This was first formulated in the Wittenberg Concord of 1536 in the formula: Nihil habet rationem sacramenti extra usum a Christo institutum ("Nothing has the character of a sacrament apart from the use instituted by Christ"). To remove any hint of doubt or superstition, the reliquiæ traditionally are either consumed, poured into the earth, or reserved (see below). In most Lutheran congregations, the administration of private communion of the sick and "shut-in" (those too feeble to attend services) involves a completely separate service of the Eucharist for which the sacramental elements are consecrated by the celebrant. Today, many Lutheran churches offer the Eucharist weekly, while others offer it less frequently. Weddings and funerals