<P> Although not a church father, but belonging to the same period, in Adomnan of Iona's biography of St Columba, the saint at one point is mentioned as meeting a woman who refuses to sleep with her husband and perform her marriage duties . When Columba meets the woman, she says that she would do anything, even to go to a monastery and become a nun, rather than to sleep with him . Columba tells the woman that the commandment of God is for her to sleep with her husband and not to leave the marriage to be a nun, because once they are married the two have become one flesh . </P> <P> The medieval Christian church, taking the lead of Augustine, developed the sacramental understanding of matrimony . However, even at this stage the Catholic Church did not consider the sacraments equal in importance . Marriage has never been considered either to be one of the sacraments of Christian initiation (Baptism, Confirmation, Eucharist) or of those that confer a character (Baptism, Confirmation, Holy Orders). </P> <P> With the development of sacramental theology, marriage was included in the select seven to which the term "sacrament" was applied . Explicit classification of marriage in this way came in reaction to the contrary teaching of Catharism that marriage and procreation are evil: the first official declaration that marriage is a sacrament was made at the 1184 Council of Verona as part of a condemnation of the Cathars . In 1208, Pope Innocent III required members of another religious movement, that of the Waldensians, to recognize that marriage is a sacrament as a condition for being received back into the Catholic Church . In 1254, Catholics accused Waldensians of condemning the sacrament of marriage, "saying that married persons sin mortally if they come together without the hope of offspring". The Fourth Lateran Council of 1215 had already stated in response to the teaching of the Cathars: "For not only virgins and the continent but also married persons find favour with God by right faith and good actions and deserve to attain to eternal blessedness ." Marriage was also included in the list of the seven sacraments at the Second Council of Lyon in 1274 as part of the profession of faith required of Michael VIII Palaiologos . The sacraments of marriage and holy orders were distinguished as sacraments that aim at the "increase of the Church" from the other five sacraments, which are intended for the spiritual perfection of individuals . The Council of Florence in 1439 again recognised marriage as a sacrament . </P> <P> The medieval view of the sacramentality of marriage has been described as follows: "Like the other sacraments, medieval writers argued, marriage was an instrument of sanctification, a channel of grace that caused God's gracious gifts and blessings to be poured upon humanity . Marriage sanctified the Christian couple by allowing them to comply with God's law for marriage and by providing them with an ideal model of marriage in Christ the bridegroom, who took the church as his bride and accorded it highest love, devotion, and sacrifice, even to the point of death ." </P>

When did marriage become a sacrament in the roman catholic church